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A244870 Number of magic labelings with magic sum n of 2nd graph shown in link. 2
1, 8, 37, 121, 318, 717, 1446, 2678, 4639, 7614, 11955, 18087, 26516, 37835, 52732, 71996, 96525, 127332, 165553, 212453, 269434, 338041, 419970, 517074, 631371, 765050, 920479, 1100211, 1306992, 1543767, 1813688, 2120120, 2466649, 2857088, 3295485 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..34.

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R. P. Stanley, Examples of Magic Labelings, Unpublished Notes, 1973 [Cached copy, with permission]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 + 3*x + 6*x^2 + 3*x^3 + x^4)/((1 - x)^6*(1 + x)).

a(n) = 7*n^5/120 + 7*n^4/16 + 35*n^3/24 + 21*n^2/8 + 149*n/60 + (-1)^n/32 + 31/32. [Bruno Berselli, Jul 08 2014]

MATHEMATICA

Table[7 n^5/120 + 7 n^4/16 + 35 n^3/24 + 21 n^2/8 + 149 n/60 + (-1)^n/32 + 31/32, {n, 0, 40}] (* Bruno Berselli, Jul 08 2014 *)

CROSSREFS

Cf. A244869-A244876.

Sequence in context: A302411 A303178 A250168 * A296537 A052387 A001780

Adjacent sequences:  A244867 A244868 A244869 * A244871 A244872 A244873

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Jul 08 2014

STATUS

approved

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Last modified March 23 05:36 EDT 2019. Contains 321422 sequences. (Running on oeis4.)