A244876 Number of magic labelings with magic sum n of 8th graph shown in link.

1, 18, 154, 813, 3157, 9880, 26429, 62713, 135470, 271285, 510485, 911840, 1558368, 2564093, 4082142, 6313934, 9519951, 14031732, 20265700, 28738335, 40083439, 55070862, 74627587, 99860383, 132081092, 172833583, 223923623, 287450506, 365841890, 461890475, 578794188

Offset

0,2

Links

Table of n, a(n) for n=0..30.

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R. P. Stanley, Examples of Magic Labelings, Unpublished Notes, 1973 [Cached copy, with permission]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, -7, -5, 22, -14, -14, 22, -5, -7, 5, -1).

Formula

G.f.: (1+13*x+71*x^2+174*x^3+238*x^4+174*x^5+71*x^6+13*x^7+x^8)/((1-x)^8*(1+x)^3).

a(n) = 3*n^7/160 + 63*n^6/320 + 151*n^5/160 + 339*n^4/128 + 2251*n^3/480 + n^2*(-1)^n/64 + 1677*n^2/320 + 3*n*(-1)^n/64 + 3259*n/960 + 9*(-1)^n/256 + 247/256. [Bruno Berselli, Jul 08 2014]

Mathematica

Table[3 n^7/160 + 63 n^6/320 + 151 n^5/160 + 339 n^4/128 + 2251 n^3/480 + n^2 (-1)^n/64 + 1677 n^2/320 + 3 n (-1)^n/64 + 3259 n/960 + 9 (-1)^n/256 + 247/256, {n, 0, 30}] (* Bruno Berselli, Jul 08 2014 *)

Crossrefs

Cf. A244869-A244876.

Sequence in context: A010934 A022613 A060221 * A171741 A197239 A060932

Adjacent sequences: A244873 A244874 A244875 * A244877 A244878 A244879

Keyword

nonn,easy

Author

N. J. A. Sloane, Jul 08 2014

Status

approved