31688

Appears in sequences

• Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 89.at n=36A031587
• Numbers k such that the least term in the periodic part of the continued fraction for sqrt(k) is 89.at n=1A031767
• Number of rooted 2-connected loopless 4-regular planar maps with n inner faces.at n=7A099553
• Triangle read by rows: T(n,k) = binomial(2n+1, n-k)*Fibonacci(2k+1), 0 <= k <= n.at n=42A103245
• 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, 0, 0), (0, -1, 0), (0, 1, -1), (0, 1, 1), (1, 0, -1)}.at n=9A149332
• Number of strings of numbers x(i=1..8) in 0..n with sum i^3*x(i)^2 equal to 512*n^2.at n=13A184309
• Solution of the complementary equation a(n) = 2*a(n-1) - a(n-3) + b(n-2), where a(0) = 2, a(1) = 4, a(2) = 6, b(0) = 1, b(1) = 3, b(2) = 5, and (a(n)) and (b(n)) are increasing complementary sequences.at n=17A295618
• Numbers k such that sopfr(k) = tau(k)^2.at n=23A305026
• a(n) is the largest number that can be expressed as the sum of three triangular numbers in exactly n ways.at n=19A330810
• Starts of runs of 4 consecutive positive negabinary-Niven numbers (A331728).at n=9A331824