26211

Appears in sequences

• a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n+1-k), where k = [ (n+1)/2 ], s = (Fibonacci numbers), t = (1, p(1), p(2), ...).at n=24A024460
• Number of polyiamonds with n cells that tile the plane isohedrally.at n=16A075223
• a(n) = 5 + floor( Sum_{j=1..n-1} a(j)/3 ).at n=30A120151
• Limit of reversed rows of triangle A126347, in which row sums equal Bell numbers (A000110).at n=24A126348
• a(n) = (n^4 + 16*n^3 + 65*n^2 + 26*n + 12)/12.at n=20A188480
• Number of 2n-bead necklaces labeled with numbers 1..4 allowing reversal, with neighbors differing by exactly 1.at n=13A208667
• Records in A175046.at n=18A319422
• Numbers k such that 459*2^k+1 is prime.at n=42A323199
• The number of squarefree numbers whose largest prime divisor is prime(n) and that are averages of twin prime pairs.at n=23A354950