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A244869 Number of magic labelings with magic sum n of first graph shown in link. 8
1, 9, 43, 143, 379, 859, 1738, 3226, 5597, 9197, 14453, 21881, 32095, 45815, 63876, 87236, 116985, 154353, 200719, 257619, 326755, 410003, 509422, 627262, 765973, 928213, 1116857, 1335005, 1585991, 1873391, 2201032, 2573000, 2993649, 3467609, 3999795, 4595415, 5259979, 5999307, 6819538 (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R. P. Stanley, Examples of Magic Labelings, Unpublished Notes, 1973 [Cached copy, with permission]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 (5,-9,5,5,-9,5,-1).

FORMULA

G.f.: (1 + 4*x + 7*x^2 + 4*x^3 + x^4) / ((1 - x)^6*(1 + x)).

From Colin Barker, Jan 11 2017: (Start)

a(n) = (15*(63 + (-1)^n) + 2592*n + 2880*n^2 + 1660*n^3 + 510*n^4 + 68*n^5) / 960.

a(n) = 5*a(n-1) - 9*a(n-2) + 5*a(n-3) + 5*a(n-4) - 9*a(n-5) + 5*a(n-6) - a(n-7) for n>6.

(End)

PROG

(PARI) Vec((1+4*x+7*x^2+4*x^3+x^4) / ((1-x)^6*(1+x)) + O(x^40)) \\ Colin Barker, Jan 11 2017

CROSSREFS

Cf. A244869-A244876.

Sequence in context: A116015 A332373 A181945 * A259181 A330088 A281773

Adjacent sequences:  A244866 A244867 A244868 * A244870 A244871 A244872

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Jul 08 2014

STATUS

approved

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Last modified August 11 03:22 EDT 2020. Contains 336421 sequences. (Running on oeis4.)