A126157 - OEIS

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A126157

Main diagonal and central terms of symmetric triangle A126155.

1, 5, 55, 1415, 69025, 5403005, 616437655, 96365988815, 19756766836225, 5140259013390005, 1654190282113104055, 645005323804145184215, 299613583126435893179425, 163464903833408195554809005

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OFFSET

0,2

LINKS

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

FORMULA

a(n)=Sum_{k, 0<=k<=n}A130847(n,k)*4^k. - Philippe Deléham, Jul 22 2007

CROSSREFS

Cf. A126155; A126156 (column 0), A126158 (diagonal).

Sequence in context: A056600 A177819 A126456 * A176267 A105715 A111821

Adjacent sequences: A126154 A126155 A126156 * A126158 A126159 A126160

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Dec 20 2006

STATUS

approved