OFFSET
1,5
COMMENTS
LINKS
G. C. Greubel, Table of n, a(n) for the first 50 rows, flattened
FORMULA
Number square T(n, k) = Sum_{j=1..min(n, k)} ceiling(j^n/n^j)*ceiling(j^k/k^j).
As a number triangle, T(n, k) = if(k<=n, Sum_{j=1..min(n-k+1, k)} ceiling(j^(n-k+1)/(n-k+1)^j)*ceiling(j^k/k^j), 0).
EXAMPLE
As a number square, rows begin
1,1,1,1,1,1,1,...
1,2,2,2,3,3,4,...
1,2,3,4,5,7,11,...
1,2,4,7,9,15,25,...
1,3,5,9,14,24,40,...
1,3,7,15,24,47,81,...
As a number triangle, rows begin
1;
1,1;
1,2,1;
1,2,2,1;
1,2,3,2,1;
1,3,4,4,3,1;
1,3,5,7,5,3,1;
MATHEMATICA
T[n_, k_] := If[k <= n, Sum[Ceiling[j^(n - k + 1)/(n - k + 1)^j]*Ceiling[j^k/k^j], {j, 1, Min[n - k + 1, k]}], 0]; Table[T[n, k], {n, 1, 20}, {k, 1, n}] // Flatten (* G. C. Greubel, Aug 30 2017 *)
PROG
(PARI) for(n=1, 20, for(k=1, n, print1(if(k<=n, sum(j=1, min(n-k+1, k), ceil(j^(n-k+1)/(n-k+1)^j)*ceil(j^k/k^j)), 0), ", "))) \\ G. C. Greubel, Aug 30 2017
CROSSREFS
KEYWORD
AUTHOR
Paul Barry, Jul 25 2005
STATUS
approved