21594

Appears in sequences

• Cycle class sequence c(n) (the number of true cycles of length n in which a certain node is included) for zeolite DDR = Deca-dodecasil 3R[Si120O240]qR starting with a T5 atom.at n=13A019112
• a(n) = self-convolution of row n of array T given by A026780.at n=7A027247
• If p(x) is the x-th prime, then the n-th set of 4 consecutive sexy prime pairs starts at p(a(n)).at n=26A095963
• Multiplicative encoding of triangle formed by reading Pascal's triangle mod 2 (A047999).at n=17A123098
• The sequence of coefficients of a polynomial recursion: p(x,n)=If[Mod[n, 2] == 0, (x + 1)*p(x, n - 1), (x^2 + (2*n - 1)*x + 1)^Floor[n/2]] ( correction).at n=48A171146
• The sequence of coefficients of a polynomial recursion: p(x,n)=If[Mod[n, 2] == 0, (x + 1)*p(x, n - 1), (x^2 + (2*n - 1)*x + 1)^Floor[n/2]] ( correction).at n=51A171146
• Number of (n+2)X(5+2) 0..1 arrays with each 3X3 subblock having clockwise perimeter pattern 00000001 00000011 or 00010011.at n=6A260764
• Number of (n+2)X(7+2) 0..1 arrays with each 3X3 subblock having clockwise perimeter pattern 00000001 00000011 or 00010011.at n=4A260766
• Let e_n(k)>=0 denote the exponent of prime(k) in the prime power representation of n. The sequence lists 1 followed by numbers n for which e_n(2*i-1)=e_n(2*i), for all i>=1.at n=38A275407
• Number of totient numbers, phi(k), k <= 10^n, whose initial digit is 1.at n=4A308945
• Under the isomorphism defined in A329329, of polynomials in GF(2)[x,y] to positive integers, a(n) is the image of the polynomial that results when x+1 is substituted for x in the polynomial with image n.at n=60A334205
• a(n) is the minimum positive integer k such that the concatenation of k, a(n-1), a(n-2), ..., a(2), and a(1) is the lesser of a pair of twin primes (i.e., a term of A001359), with a(1) = 11.at n=39A350246
• Products of four distinct primes between sphenic numbers (products of 3 distinct primes).at n=11A351382
• G.f. satisfies A(x) = exp( Sum_{k>=1} (A(x^k) + A(i*x^k) + A(-x^k) + A(i^3*x^k))/4 * x^k/k ), where i = sqrt(-1).at n=41A363405