31977

Appears in sequences

• Distinct odd elements in the 5-Pascal triangle A028313.at n=47A028319
• a(n) = (n-3)*A006918(n-2)/2 for n >= 2, with a(0) = a(1) = 0.at n=36A038376
• Indices of pentagonal numbers which are also triangular.at n=5A046174
• Indices of pentagonal numbers that are also hexagonal.at n=2A046178
• Partial sums of A007585.at n=16A051797
• Numbers k such that 299*2^k + 1 is prime.at n=29A053366
• Generalized centered polygonal numbers.at n=17A081282
• An interleaved sequence of pyramidal and polygonal numbers.at n=33A081284
• Denominator of 2*Sum(C(n,w)/(2*w+1),w=0..n/2-1)+C(n,n/2)/(n+1) if n is even, or of 2*Sum(C(n,w)/(2*w+1),w=0..(n-1)/2) if n is odd.at n=31A085569
• Number of walks of length n between two nodes at distance 4 in the cycle graph C_9.at n=14A095369
• a(-1) = a(0) = 0, a(1) = 1; a(n) = 5a(n-1) - 5a(n-2) + a(n-3) + 2*(-1)^(n+1), alternatively a(n) = 3a(n-1) + 3a(n-2) - a(n-3).at n=9A109437
• Limiting sequence of second differences of certain Poincaré series [or Poincare series] expansions.at n=10A124640
• Smallest number expressible in the form a^2 + 2b^2, with positive integers a and b, in exactly n ways.at n=11A200977
• The Wiener index of the para-polyphenyl chain with n hexagons (see the Dou et al. and the Deng references).at n=10A216112
• a(0) = 1, a(1) = 2, a(2n) = A019565(a(n)), a(2n+1) = A065642(a(n)).at n=65A285332
• Numbers n such that 13^n is the highest power of 13 dividing A240751(n).at n=15A286007
• Triangle read by rows, T(n, k) = binomial(2*n-1, 2*k-1) * binomial(2*n-2*k, n-k) * (k+1) / binomial(n+k+1, n-k) for 0 <= k <= n.at n=60A337841
• Numbers of squares and rectangles of all sizes in 3*n*(n+1)/2-ominoes in form of three-quarters of Aztec diamonds.at n=17A338996
• Smallest number having exactly n divisors of the form 8*k + 1.at n=11A343104
• Smallest number having exactly n divisors of the form 8*k + 3.at n=12A343105