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A244875 Number of magic labelings with magic sum n of 7th graph shown in link. 2
1, 21, 179, 938, 3612, 11242, 29947, 70855, 152720, 305330, 573812, 1023939, 1748545, 2875153, 4574922, 7073018, 10660515, 15707931, 22680505, 32155320, 44840378, 61595732, 83456781, 111659833, 147670042, 193211824, 250301858, 321284777, 408871655, 516181395 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Colin Barker, Table of n, a(n) for n = 0..1000

N. J. A. Sloane, Graphs for A244869-A244876.

R. P. Stanley, Examples of Magic Labelings, Unpublished Notes, 1973 [Cached copy, with permission]

Index entries for linear recurrences with constant coefficients, signature (7,-20,28,-14,-14,28,-20,7,-1).

FORMULA

G.f.: (1 + 14*x + 52*x^2 + 77*x^3 + 52*x^4 + 14*x^5 + x^6) / ((1 - x)^8*(1 + x)).

a(n) = (315*(255+(-1)^n) + 306144*n + 498456*n^2 + 452312*n^3 + 250530*n^4 + 86576*n^5 + 17724*n^6 + 1688*n^7) / 80640. - Colin Barker, Jan 11 2017

PROG

(PARI) Vec((1 + 14*x + 52*x^2 + 77*x^3 + 52*x^4 + 14*x^5 + x^6) / ((1 - x)^8*(1 + x)) + O(x^40)) \\ Colin Barker, Jan 11 2017

CROSSREFS

Cf. A244869, A244870, A244871, A244872, A244873, A244874, A244876.

Sequence in context: A090021 A254681 A219625 * A025604 A219412 A062159

Adjacent sequences:  A244872 A244873 A244874 * A244876 A244877 A244878

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Jul 08 2014

STATUS

approved

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Last modified July 24 21:41 EDT 2021. Contains 346273 sequences. (Running on oeis4.)