A186339 a(n) = A006125(n+1) * 2^A001840(n).

1, 4, 32, 512, 32768, 4194304, 1073741824, 1099511627776, 2251799813685248, 9223372036854775808, 151115727451828646838272, 4951760157141521099596496896, 324518553658426726783156020576256, 85070591730234615865843651857942052864

Offset

0,2

Comments

Hankel transform of A186338.

Links

Table of n, a(n) for n=0..13.

Formula

a(n) = 2^binomial(n+1,2) * 2^floor((n+1)*(n+2)/6).

a(n) = 2^A320259(n). - Amiram Eldar, Jan 24 2026

Mathematica

a[n_] := 2^Quotient[(n+1)*(2*n+1), 3]; Array[a, 15, 0] (* Amiram Eldar, Jan 24 2026*)

Crossrefs

Cf. A001840, A006125, A186338, A320259.

Sequence in context: A118990 A127945 A036442 * A086899 A219149 A013041

Adjacent sequences: A186336 A186337 A186338 * A186340 A186341 A186342

Keyword

nonn,easy

Author

Paul Barry, Feb 18 2011

Status

approved