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A244864
a(n) = binomial(n+5,5) + 4*binomial(n+4,5) + 4*binomial(n+3,5) + binomial(n+2,5).
2
1, 10, 49, 165, 440, 1001, 2030, 3774, 6555, 10780, 16951, 25675, 37674, 53795, 75020, 102476, 137445, 181374, 235885, 302785, 384076, 481965, 598874, 737450, 900575, 1091376, 1313235, 1569799, 1864990, 2203015, 2588376, 3025880, 3520649, 4078130, 4704105, 5404701, 6186400, 7056049
OFFSET
0,2
LINKS
R. P. Stanley, Examples of Magic Labelings, Unpublished Notes, 1973 [Cached copy, with permission]
FORMULA
G.f.: (x+1)*(x^2+3*x+1)/(x-1)^6; a(n) = (2*n+3)*(n+2)*(n+1)*(n^2+3*n+4)/24. - Alois P. Heinz, Jul 11 2014
a(n) = Sum_{k=A000292(n)..A000292(n+1)} k. - J. M. Bergot, Feb 25 2015
MAPLE
a:= n-> (2*n+3)*(n+2)*(n+1)*(n^2+3*n+4)/24:
seq(a(n), n=0..40); # Alois P. Heinz, Jul 11 2014
MATHEMATICA
Table[Binomial[n+5, 5]+4*Binomial[n+4, 5]+4*Binomial[n+3, 5]+ Binomial[ n+2, 5], {n, 0, 40}] (* or *) LinearRecurrence[{6, -15, 20, -15, 6, -1}, {1, 10, 49, 165, 440, 1001}, 40] (* Harvey P. Dale, Nov 13 2014 *)
a[n_] := (2 n^5 + 15 n^4 + 48 n^3 + 81 n^2 + 70 n + 24)/ 24; Array[a, 40, 0] (* or *)
CoefficientList[Series[(x^3 + 4 x^2 + 4 x + 1)/(x - 1)^6, {x, 0, 40}], x] (* Robert G. Wilson v, Feb 26 2015 *)
PROG
(PARI) a(n)=(2*n+3)*(n+2)*(n+1)*(n^2+3*n+4)/24 \\ Charles R Greathouse IV, Oct 21 2022
CROSSREFS
Sequence in context: A226797 A163716 A271662 * A051947 A274561 A253221
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Jul 07 2014
STATUS
approved