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A125198 Number of magical labelings of the octahedral graph of magic sum n. 0
1, 8, 40, 144, 417, 1032, 2272, 4568, 8545, 15072, 25320, 40824, 63553, 95984, 141184, 202896, 285633, 394776, 536680, 718784, 949729, 1239480, 1599456, 2042664, 2583841, 3239600, 4028584, 4971624, 6091905, 7415136, 8969728 (list; graph; refs; listen; history; internal format)
OFFSET

0,2

LINKS

M. M. Ahmed, Algebraic Combinatorics of Magic Squares, math.CO/0405476, p73.

FORMULA

Empirical G.f.: (1+2*x+6*x^2+2*x^3+x^4)/(1-x)^7/(1+x). [Colin Barker, Feb 12 2012]

MAPLE

a := proc(r) local r2 ; r2 := r^6/120+r^5/10+25*r^4/48+3*r^3/2+38*r^2/15+12*r/5 ; if r mod 2 = 0 then r2+1 ; else r2+15/16 ; fi ; end: for n from 0 to 40 do printf("%d ", a(n)) ; od;

CROSSREFS

Sequence in context: A162668 A191903 A028596 * A128639 A004405 A001789

Adjacent sequences:  A125195 A125196 A125197 * A125199 A125200 A125201

KEYWORD

easy,nonn,changed

AUTHOR

R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jan 25 2007

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Last modified February 15 09:06 EST 2012. Contains 205746 sequences.