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A253285
a(n) = RF(n+1,3)*C(n+2,n-1), where RF(a,n) is the rising factorial.
3
0, 24, 240, 1200, 4200, 11760, 28224, 60480, 118800, 217800, 377520, 624624, 993720, 1528800, 2284800, 3329280, 4744224, 6627960, 9097200, 12289200, 16364040, 21507024, 27931200, 35880000, 45630000, 57493800, 71823024, 89011440, 109498200, 133771200, 162370560
OFFSET
0,2
FORMULA
G.f.: -24/(x-1)^4 - 144/(x-1)^5 - 240/(x-1)^6 - 120/(x-1)^7. See the comment in A253284 for the general case.
a(n) = n*((n+1)*(n+2))^2*(n+3)/6.
a(n) = (N^3 + 4*N^2 + 4*N)/6 = N*(N + 2)^2/6 with N = n^2 + 3*n.
From Bruno Berselli, Mar 06 2018: (Start)
a(n) = 24*A006542(n+3) for n>0.
a(n) = Sum_{i=0..n} i*(i+1)^3*(i+2). Therefore, the first differences are in A133754. (End)
MAPLE
seq(n*((n+1)*(n+2))^2*(n+3)/6, n=0..19);
MATHEMATICA
Table[n ((n + 1) (n + 2))^2 (n + 3)/6, {n, 0, 40}] (* Bruno Berselli, Mar 06 2018 *)
LinearRecurrence[{7, -21, 35, -35, 21, -7, 1}, {0, 24, 240, 1200, 4200, 11760, 28224}, 40] (* Harvey P. Dale, Aug 05 2024 *)
PROG
(Sage) [n*((n+1)*(n+2))^2*(n+3)/6 for n in (0..40)] # Bruno Berselli, Mar 06 2018
(GAP) List([0..40], n -> n*((n+1)*(n+2))^2*(n+3)/6); # Bruno Berselli, Mar 06 2018
(Magma) [n*((n+1)*(n+2))^2*(n+3)/6: n in [0..40]]; // Bruno Berselli, Mar 06 2018
(Python) [n*((n+1)*(n+2))**2*(n+3)/6 for n in range(40)] # Bruno Berselli, Mar 06 2018
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Peter Luschny, Mar 23 2015
STATUS
approved