Sequences

392,541 sequences

a(n) = a(n-1) + a(n-2) + 1, with a(0) = 0 and a(1) = 2.A001610
a(n) = a(n-1) + a(n-2) + 1, with a(0) = 0 and a(1) = 2.
a(n) = Fibonacci(n) + 1.A001611
a(n) = Fibonacci(n) + 1.
a(n) = a(n-1) + a(n-2) - 1 for n > 1, a(0)=3, a(1)=2.A001612
a(n) = a(n-1) + a(n-2) - 1 for n > 1, a(0)=3, a(1)=2.
Delete all odd digits from n.A001613
Delete all odd digits from n.
Connell sequence: 1 odd, 2 even, 3 odd, ...A001614
Connell sequence: 1 odd, 2 even, 3 odd, ...
Dedekind psi function: n * Product_{p|n, p prime} (1 + 1/p).A001615
Dedekind psi function: n * Product_{p|n, p prime} (1 + 1/p).
Number of parabolic vertices of Gamma_0(n).A001616
Number of parabolic vertices of Gamma_0(n).
Genus of modular group Gamma_0(n). Or, genus of modular curve X_0(n).A001617
Genus of modular group Gamma_0(n). Or, genus of modular curve X_0(n).
Nearest integer to 2*n*log(n).A001618
Nearest integer to 2*n*log(n).
Number of letters in English name for n increases at these numbers.A001619
Number of letters in English name for n increases at these numbers.
Decimal expansion of Euler's constant (or the Euler-Mascheroni constant), gamma.A001620
Decimal expansion of Euler's constant (or the Euler-Mascheroni constant), gamma.
a(n) = n*(n + 1)*(n^2 + n + 2)/4.A001621
a(n) = n*(n + 1)*(n^2 + n + 2)/4.
Decimal expansion of golden ratio phi (or tau) = (1 + sqrt(5))/2.A001622
Decimal expansion of golden ratio phi (or tau) = (1 + sqrt(5))/2.
Number of 3 X n reduced (normalized) Latin rectangles.A001623
Number of 3 X n reduced (normalized) Latin rectangles.
Related to Latin rectangles.A001624
Related to Latin rectangles.
Related to Latin rectangles.A001625
Related to Latin rectangles.
Number of 3-line Latin rectangles.A001626
Number of 3-line Latin rectangles.
Related to Latin rectangles.A001627
Related to Latin rectangles.
Convolved Fibonacci numbers.A001628
Convolved Fibonacci numbers.
Self-convolution of Fibonacci numbers.A001629
Self-convolution of Fibonacci numbers.
Tetranacci numbers: a(n) = a(n-1) + a(n-2) + a(n-3) + a(n-4), with a(0)=a(1)=0, a(2)=1, a(3)=2.A001630
Tetranacci numbers: a(n) = a(n-1) + a(n-2) + a(n-3) + a(n-4), with a(0)=a(1)=0, a(2)=1, a(3)=2.
Tetranacci numbers: a(n) = a(n-1) + a(n-2) + a(n-3) + a(n-4), with initial conditions a(0..3) = (0, 0, 1, 0).A001631
Tetranacci numbers: a(n) = a(n-1) + a(n-2) + a(n-3) + a(n-4), with initial conditions a(0..3) = (0, 0, 1, 0).
Smallest prime p such that there is a gap of 2n between p and previous prime.A001632
Smallest prime p such that there is a gap of 2n between p and previous prime.
Numbers with an odd number of digits.A001633
Numbers with an odd number of digits.
a(n) = a(n-2) + a(n-3) + a(n-4), with initial values a(0) = 0, a(1) = 2, a(2) = 3, a(3) = 6.A001634
a(n) = a(n-2) + a(n-3) + a(n-4), with initial values a(0) = 0, a(1) = 2, a(2) = 3, a(3) = 6.
A Fielder sequence: a(n) = a(n-1) + a(n-2) - a(n-6), n >= 7.A001635
A Fielder sequence: a(n) = a(n-1) + a(n-2) - a(n-6), n >= 7.
A Fielder sequence: a(n) = a(n-1) + a(n-2) - a(n-7), n >= 8.A001636
A Fielder sequence: a(n) = a(n-1) + a(n-2) - a(n-7), n >= 8.
Numbers with an even number of digits.A001637
Numbers with an even number of digits.
A Fielder sequence: a(n) = a(n-1) + a(n-3) + a(n-4), n >= 4.A001638
A Fielder sequence: a(n) = a(n-1) + a(n-3) + a(n-4), n >= 4.
A Fielder sequence. a(n) = a(n-1) + a(n-3) + a(n-4) + a(n-5), n >= 6.A001639
A Fielder sequence. a(n) = a(n-1) + a(n-3) + a(n-4) + a(n-5), n >= 6.
A Fielder sequence.A001640
A Fielder sequence.
A Fielder sequence: a(n) = a(n-1) + a(n-2) + a(n-4).A001641
A Fielder sequence: a(n) = a(n-1) + a(n-2) + a(n-4).
A Fielder sequence.A001642
A Fielder sequence.
A Fielder sequence.A001643
A Fielder sequence.
a(n) = a(n-1) + a(n-2) + a(n-3), a(0)=3, a(1)=1, a(2)=3.A001644
a(n) = a(n-1) + a(n-2) + a(n-3), a(0)=3, a(1)=1, a(2)=3.
A Fielder sequence.A001645
A Fielder sequence.
Number of self-dual codes of length 2n over GF(4).A001646
Number of self-dual codes of length 2n over GF(4).
Number of indecomposable self-dual codes of length 2n over GF(4).A001647
Number of indecomposable self-dual codes of length 2n over GF(4).
Tetranacci numbers A073817 without the leading term 4.A001648
Tetranacci numbers A073817 without the leading term 4.
A Fielder sequence.A001649
A Fielder sequence.
k appears k times (k odd).A001650
k appears k times (k odd).
Numbers not divisible by 3.A001651
Numbers not divisible by 3.
a(n) = 6*a(n-1) - a(n-2) + 2 with a(0) = 0, a(1) = 3.A001652
a(n) = 6*a(n-1) - a(n-2) + 2 with a(0) = 0, a(1) = 3.
Numbers k such that 2*k^2 - 1 is a square.A001653
Numbers k such that 2*k^2 - 1 is a square.
Golden rectangle numbers: F(n) * F(n+1), where F(n) = A000045(n) (Fibonacci numbers).A001654
Golden rectangle numbers: F(n) * F(n+1), where F(n) = A000045(n) (Fibonacci numbers).
Fibonomial coefficients: a(n) = F(n+1) * F(n+2) * F(n+3)/2, where F() = Fibonacci numbers A000045.A001655
Fibonomial coefficients: a(n) = F(n+1) * F(n+2) * F(n+3)/2, where F() = Fibonacci numbers A000045.
Fibonomial coefficients.A001656
Fibonomial coefficients.
Fibonomial coefficients: column 5 of A010048.A001657
Fibonomial coefficients: column 5 of A010048.
Fibonomial coefficients.A001658
Fibonomial coefficients.
Expansion of bracket function.A001659
Expansion of bracket function.