18667

Appears in sequences

• Total number of parts in all compositions of n into distinct odd parts.at n=44A097936
• Sums of p-th to the q-th prime where p and q are twin primes.at n=30A114379
• a(0)=2. a(n) = the a(n-1)th integer from among those positive integers coprime to n.at n=18A125554
• a(n) = floor((x^n-(1-x)^n)/sqrt(7)+1/2) where x = (sqrt(7)+1)/2.at n=17A136425
• Ulam's spiral (SSW spoke).at n=34A143838
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 0), (-1, 0, 0), (0, -1, 1), (0, 1, -1), (1, 0, 1)}.at n=9A148928
• G.f. satisfies: A(x) = A(x^2)^2 + x*A(x)^2.at n=9A182144
• G.f. satisfies: A(x) = ( A(x^2) + x*A(x) )^2.at n=8A182325
• Upper s-Wythoff sequence, where s=A081276 (eighth cubes). Complement of A184431.at n=51A184432
• Number of Poulet numbers (or pseudoprimes to base 2, A001567) less than 2^n.at n=33A208276
• Expansion of Product_{k>=1} ((1 + x^(2*k-1))/(1 - x^(2*k)))^k.at n=25A295832
• Mark each point on the n X n X n X n grid with the number of points that are visible from it; a(n) is the number of distinct values in the grid.at n=56A339947
• a(n) = 6*binomial(n,4) + 2*binomial(n,2) + 1.at n=18A341703