20548

Appears in sequences

• Coordination sequence for sigma-CrFe, Position Xc.at n=36A009961
• Numbers whose base-4 representation contains exactly four 0's and four 1's.at n=24A045037
• Number of pentagonal regions in regular n-gon with all diagonals drawn.at n=39A067152
• a(n) = A000695(A014486(n)).at n=14A083931
• Largest number that is not the sum of five n-gonal numbers.at n=29A118367
• A106486-encodings of combinatorial games with value 2.at n=28A125995
• Number of increasing sequences of n integers x(1),...,x(n) with values in 1..3*n such that x(j) divides x(k) if j divides k.at n=12A180385
• E.g.f.: exp(-1)*Sum_{n>=0} (1+x)^(n^3)/n!.at n=3A211250
• Lengths of runs of the initial digits of semiprimes in decimal representation, cf. A239634.at n=43A239639
• Number of length n arrays of permutations of 0..n-1 with each element moved by -3 to 3 places and every three consecutive elements having its maximum within 3 of its minimum.at n=22A263692
• Group the natural numbers into groups (1),(2),(3),(4),(5,6),(7,8,9),... so that the n-th group contains N(n) terms, where N(n) is the Narayana's cows sequence (A000930). Sequence contains the sum of the terms in the n-th group.at n=14A301877