A110539 Diagonal sums of A110537 viewed as a number triangle.

1, 1, 2, 3, 4, 5, 8, 10, 15, 23, 35, 58, 101, 193, 381, 817, 1820, 4298, 10550, 27037, 71715, 197062, 558923, 1635948, 4932931, 15313467, 48883315, 160311731, 539527417, 1861545528, 6578404569, 23788920636, 87961893345, 332339327570

Offset

1,3

Links

G. C. Greubel, Table of n, a(n) for n = 1..750

Formula

a(n) = Sum_{k=1..floor((n+1)/2)} Sum_{j=1..min(n-2k+2, k)} ceiling(j^(n-2k+2)/(n-2k+2)^j)*ceiling(j^k/k^j).

Mathematica

A110539[n_] := Sum[Sum[ Ceiling[j^(n - 2*k + 2)/(n - 2*k + 2)^j] *Ceiling[j^k/k^j], {j, 1, Min[n - k + 1, k]}], {k, 1, Floor[n/2]}];
Table[A110539[n], {n, 1, 50}] (* G. C. Greubel, Aug 31 2017 *)

Prog

(PARI) for(n=1, 25, print1(sum(k=1, floor((n+1)/2), sum(j=1, min(n-2k+2, k), ceil(j^(n-2k+2)/(n-2k+2)^j)*ceil(j^k/k^j))), ", ")) \\ G. C. Greubel, Aug 31 2017

Crossrefs

Sequence in context: A035555 A039875 A206555 * A222297 A211981 A019997

Adjacent sequences: A110536 A110537 A110538 * A110540 A110541 A110542

Keyword

easy,nonn

Author

Paul Barry, Jul 25 2005

Status

approved