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A125196
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Number of magic labelings of the Petersen graph with magic sum n.
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1
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1, 6, 27, 87, 228, 513, 1034, 1914, 3315, 5440, 8541, 12921, 18942, 27027, 37668, 51428, 68949, 90954, 118255, 151755, 192456, 241461, 299982, 369342, 450983, 546468, 657489, 785869, 933570, 1102695, 1295496
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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0,2
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LINKS
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Vincenzo Librandi, Table of n, a(n) for n = 0..1000
M. M. Ahmed, Algebraic Combinatorics of Magic Squares, math.CO/0405476.
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FORMULA
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G.f.: (x^4+x^3+6x^2+x+1)/(1-x)^6/(1+x) [Ahmed].
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MAPLE
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a := proc(r) local r1 ; r1 := r^5/24+5*r^4/16+25*r^3/24+15*r^2/8+23*r/12 ; if r mod 2 = 0 then r1+1 ; else r1+13/16 ; fi ; end: for n from 0 to 30 do printf("%d ", a(n)) ; od;
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MATHEMATICA
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CoefficientList[Series[(x^4 + x^3 + 6x^2 + x + 1)/(1 - x)^6/(1 + x), {x, 0, 40}], x] (* Vincenzo Librandi, Dec 12 2012 *)
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CROSSREFS
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Sequence in context: A124089 A100188 A131985 * A100189 A052267 A038166
Adjacent sequences: A125193 A125194 A125195 * A125197 A125198 A125199
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KEYWORD
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easy,nonn
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AUTHOR
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R. J. Mathar, Jan 25 2007
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STATUS
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approved
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