cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A127098 Triangle T(n,m) read by rows: product A127093 * A127094.

Original entry on oeis.org

1, 5, 2, 10, 0, 3, 21, 2, 8, 4, 26, 0, 0, 0, 5, 50, 2, 3, 18, 12, 6, 50, 0, 0, 0, 0, 0, 7, 85, 2, 8, 4, 32, 0, 16, 8, 91, 0, 3, 0, 0, 0, 27, 0, 9, 130, 2, 0, 0, 5, 50, 0, 0, 20, 10, 122, 0, 0, 0, 0, 0, 0, 0, 0, 0, 11, 210, 2, 11, 22, 12, 6, 72, 0, 48, 36, 24, 12, 170, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 13, 250, 2, 0, 0, 0, 0, 7, 98, 0
Offset: 1

Views

Author

Gary W. Adamson, Jan 05 2007

Keywords

Comments

A127097 is a close companion.

Examples

			First few rows of the triangle are:
1;
5, 2;
10, 0, 3;
21, 2, 8, 4;
26, 0, 0, 0, 5;
50, 2, 3, 18, 12, 6;
50, 0, 0, 0, 0, 0, 7;
85, 2, 8, 4, 32, 0, 16, 8;
		

Crossrefs

Programs

  • Maple
    A127093 := proc(n,m) if m> n or m<1 or n < 1 then 0 ; elif (n mod m) = 0 then m; else 0 ; fi; end:
    A127094 := proc(n,m) A127093(n,n-m+1) ; end: A127098 := proc(n,m) add( A127093(n,k)*A127094(k,m),k=1..n) ; end:
    for n from 1 to 30 do for m from 1 to n do printf("%d,",A127098(n,m)) ; od: od: # R. J. Mathar, Mar 02 2009

Formula

T(n,m) = Sum_{k=m..n} A127093(n,k)*A127094(k,m).
Row sums: Sum_{m=1..n} T(n,m) = A001001(n).
Left column: T(1,m) = A001157(m).

Extensions

Edited and extended by R. J. Mathar, Mar 02 2009