19985

Appears in sequences

• Triangle read by rows: T(n,k), n >=1, 0 <= k <= C(n,k), = number of n X n symmetric positive definite matrices with 2's on the main diagonal and 1's and 0's elsewhere and with k 1's above the diagonal.at n=67A080858
• Numbers k such that 2^k + 11 is prime.at n=22A102633
• Numbers k such that 2*k+1, 3*k+2, 4*k+3 and 5*k+4 are primes.at n=20A138700
• Numbers that match polynomials over {0,1} that have a factor containing -3 as a coefficient; see Comments.at n=27A208182
• Number of compositions (ordered partitions) of n into distinct parts where no part is a multiple of 4.at n=34A332310
• a(n) = Sum_{1 <= x_1 <= x_2 <= x_3 <= x_4 <= n} gcd(x_1, x_2, x_3 , x_4, n).at n=23A343518
• Number of partitions of n into 6 or more distinct parts.at n=48A347573
• Number of k <= P(n) such that rad(k) | P(n), where rad(n) = A007947(n) and P(n) = A002110(n).at n=8A363061