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A172634 Number of n X 3 0..2 arrays with row sums 3 and column sums n. 2
1, 7, 31, 175, 991, 5881, 35617, 219871, 1376095, 8710537, 55644337, 358198369, 2320792657, 15120204295, 98984058271, 650725327231, 4293779332927, 28425752310361, 188739799967425, 1256510215733185, 8385127334900305 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

R. H. Hardin, Table of n, a(n) for n=1..99

FORMULA

Empirical: n^2*a(n) = (2*n-1)^2*a(n-1) + 19*(n-1)^2*a(n-2) + 14*(n-2)*(n-1)*a(n-3). - Vaclav Kotesovec, Oct 19 2012

Conjecture: equals A208446, the inverse binomial transform of the Franel numbers (A000172), starting at offset=1. - Paul D. Hanna, Nov 02 2012

CROSSREFS

Cf. A208446.

Sequence in context: A102239 A188233 A264608 * A208446 A139151 A139060

Adjacent sequences:  A172631 A172632 A172633 * A172635 A172636 A172637

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 06 2010

STATUS

approved

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Last modified November 18 10:38 EST 2017. Contains 294887 sequences.