18836

Appears in sequences

• a(n) = 1*prime(n) + 2*prime(n-1) + ... + k*prime(n+1-k), where k=floor((n+1)/2) and prime(n) is the n-th prime.at n=37A023870
• a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (natural numbers), t = (primes).at n=36A024867
• Partial sums of A045699.at n=42A178494
• Number of acute isosceles triangles on an n X n grid.at n=12A190317
• Number of (n+2) X (1+2) 0..1 arrays with every 2 X 2 and 3 X 3 subblock diagonal maximum minus antidiagonal minimum nondecreasing horizontally and vertically.at n=28A253503
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 1", based on the 5-celled von Neumann neighborhood.at n=30A269908
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 275", based on the 5-celled von Neumann neighborhood.at n=29A271093
• Numbers k such that 2^m == 2 (mod m*(m+1)), where m = A019320(k).at n=30A297414
• Numbers k such that A019320(k) is in A217465.at n=22A297415
• G.f.: Sum_{k>=1} x^(2*k-1)/(1-x^(2*k-1)) * Product_{k>=1} (1+x^k)/(1-x^k).at n=19A305105
• Number of binary words of length n with three times as many occurrences of subword 101 as occurrences of subword 010.at n=18A307795