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.

A144061 Eigentriangle generated from A109128, row sums = expansion of {2(exp(x)-1)}.

Original entry on oeis.org

1, 1, 1, 1, 3, 2, 1, 5, 10, 6, 1, 7, 22, 42, 22, 1, 9, 38, 114, 198, 94, 1, 11, 58, 234, 638, 1034, 454, 1, 13, 82, 414, 1518, 3854, 5902, 2430, 1, 15, 110, 666, 3058, 10434, 24970, 36450, 14214, 1, 17, 142, 1002, 5522, 23594, 75818, 172530, 241638, 89918
Offset: 1

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Row sums = A001861: (1, 2, 6, 22, 94, 454, 2430,...) = expansion of {2(exp(x)-1)}
Right border = A001861 shifted: (1, 1, 2, 6, 22, 94,...).
Sum of n-th row terms = rightmost term of next row.

Examples

			First few rows of the triangle =
1;
1, 1;
1, 3, 2;
1, 5, 10, 6;
1, 7, 22, 42, 22;
1, 9, 38, 114, 198, 94;
1, 11, 58, 234, 638, 1034, 454;
1, 13, 82, 414, 1518, 3854, 5902, 2430;
1, 15, 110, 666, 3058, 10434, 24970, 36450, 14214;
...
Example: row 3 = (1, 5, 10, 6) = termwise products of (1, 5, 5, 1) and (1, 1, 2, 6), where (1, 5, 5, 1) = row 3 of triangle A109128 and (1, 1, 2, 6) = the first 4 terms of A001861 shifted.
		

Crossrefs

Formula

T(n,k) = A109128(n,k)*A001861(k-1).
A109128 = (2*binomial(n,k) - 1): (1; 1,1; 1,3,1; 1,5,5,1;...).
A001861(k-1) = A001861 shifted one place, = (1, 1, 2, 6, 22, 94, 454,...).