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A130515 In triangular peg solitaire, number of distinct feasible pairs starting with one peg missing and finishing with one peg. 2
1, 4, 3, 17, 29, 27, 80, 125, 108, 260, 356, 300, 637, 832, 675, 1341, 1665, 1323, 2500, 3025, 2352, 4304, 5072, 3888, 6929, 8036, 6075, 10625, 12125, 9075, 15616, 17629, 13068, 22212, 24804, 18252, 30685, 34000, 24843, 41405, 45521 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,2

COMMENTS

Coincides with A130516 for n >= 6.

LINKS

George I. Bell, Table of n, a(n) for n = 2..52

George I. Bell, Solving Triangular Peg Solitaire [arXiv:math/0703865v4]

FORMULA

Reference gives an explicit formula for a(n).

PROG

(PARI) a(n) = {my(T = n*(n+1)/2); if (n % 3 == 1, (T-1)^2/27, if ( n % 2 == 0, (4*T^2 + 9*n^2)/72, (4*T^2 + 9*(n+1)^2)/72; ); ); }  \\ Michel Marcus, Apr 21 2013

CROSSREFS

Cf. A130516.

Sequence in context: A060509 A113203 A034486 * A161893 A192773 A183231

Adjacent sequences:  A130512 A130513 A130514 * A130516 A130517 A130518

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Aug 09 2007

EXTENSIONS

More terms from George I. Bell (gibell(AT)comcast.net), Sep 27 2007

STATUS

approved

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Last modified April 18 14:05 EDT 2014. Contains 240720 sequences.