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A113596
P(P(n))-P(P(n-1)), where P(n) = n(n+1)(n+2)/6 (cf. A000292).
1
0, 1, 19, 200, 1320, 6230, 23086, 71484, 192900, 467115, 1036585, 2140996, 4164524, 7698600, 13623260, 23210440, 38252856, 61222389, 95462175, 145416880, 216905920, 317444666, 456618954, 646518500, 902235100, 1242431775, 1689989301, 2272736844
OFFSET
0,3
FORMULA
From Chai Wah Wu, May 28 2016 : (Start)
a(n) = 9*a(n-1) - 36*a(n-2) + 84*a(n-3) - 126*a(n-4) + 126*a(n-5) - 84*a(n-6) + 36*a(n-7) - 9*a(n-8) + a(n-9)
G.f.: x*(4*x^5 + 80*x^4 + 120*x^3 + 65*x^2 + 10*x + 1)/(1 - x)^9 (End)
PROG
(PARI) P(n) = n*(n+1)*(n+2)/6;
a(n) = P(P(n)) - P(P(n-1)); \\ Michel Marcus, Sep 16 2013
CROSSREFS
Sequence in context: A241021 A055558 A160452 * A155670 A085770 A002501
KEYWORD
easy,nonn
AUTHOR
Amarnath Murthy, Nov 07 2005
EXTENSIONS
Better description from Jonathan Vos Post, Nov 11 2005
Edited by N. J. A. Sloane, Nov 11, 2005
STATUS
approved