Sequences

Square triangular numbers: numbers that are both triangular and square.

Number of inequivalent Hadamard designs of order 4n.

A continued fraction.

Decimal expansion of e.

Increasing blocks of digits of e.

Maximal number of pairwise relatively prime polynomials of degree n over GF(2).

Maximal kissing number of an n-dimensional lattice.

a(n) = 3^n - 3*2^n + 3.

Number of labeled ordered set partitions into 5 parts for n>=1, a(0)=1.

Number of skew-symmetric Hadamard matrices of order 4n.

a(0) = a(1) = 1; for n > 1, a(n) = n*a(n-1) + (-1)^n.

Number of doubly-regular tournaments of order 4n-1.

Primes with primitive root 2.

Primes with 3 as smallest primitive root.

Primes with 5 as smallest primitive root.

Primes with 6 as smallest primitive root.

Primes with 7 as smallest primitive root.

Trajectory of 1 under map x->x + (x-with-digits-reversed).

Reverse digits of previous term and multiply by previous term.

Iccanobif numbers: reverse digits of two previous terms and add.

Number of graphical basis partitions of 2n.

Number of red-black rooted trees with n-1 internal nodes.

Primes == +-1 (mod 8).

Primes p such that the multiplicative order of 2 modulo p is (p-1)/3.

Primes p such that the multiplicative order of 2 modulo p is (p-1)/4.

Primes p such that the multiplicative order of 2 modulo p is (p-1)/5.

Primes p such that the multiplicative order of 2 modulo p is (p-1)/6.

Number of black-rooted red-black trees with n internal nodes.

Red rooted red-black trees with n internal nodes.

Number of stable feedback shift registers with n stages.

Describe the previous term! (method A - initial term is 4).

Describe the previous term! (method A - initial term is 5).

a(n) = Product_{k=1..n} k^(2k - 1 - n).

Describe the previous term! (method A - initial term is 6).

An exponential function on partitions (next term is 2^512).

Describe the previous term! (method A - initial term is 7).

a(n) = 2^(2^n).

Double factorial of odd numbers: a(n) = (2*n-1)!! = 1*3*5*...*(2*n-1).

Final digit of 3^n.

A self-generating sequence: a(1)=1, a(2)=2, a(n+1) chosen so that a(n+1)-a(n-1) is the first number not obtainable as a(j)-a(i) for 1<=i<j<=n.

Number of n-input 2-output switching networks with GL(n,2) acting on the input and S(2) and C(2,2) acting on the output.

Describe the previous term! (method A - initial term is 8).

Number of n-input 3-output switching networks with GL(n,2) acting on the input and S(3) and C(2,3) acting on the output.

Degrees of primitive irreducible trinomials: n such that 2^n - 1 is a Mersenne prime and x^n + x^k + 1 is a primitive irreducible polynomial over GF(2) for some k with 0 < k < n.

Describe the previous term! (method A - initial term is 9).

Describe the previous term! (method A - initial term is 0).

Number of partitions of n into squares.

a(n) = sigma_2(n): sum of squares of divisors of n.

sigma_3(n): sum of cubes of divisors of n.

sigma_4(n): sum of 4th powers of divisors of n.