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A099761
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a(n) = (n*(n+2))^2.
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3
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0, 9, 64, 225, 576, 1225, 2304, 3969, 6400, 9801, 14400, 20449, 28224, 38025, 50176, 65025, 82944, 104329, 129600, 159201, 193600, 233289, 278784, 330625, 389376, 455625, 529984, 613089, 705600, 808201, 921600, 1046529, 1183744, 1334025
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OFFSET
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0,2
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LINKS
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Table of n, a(n) for n=0..33.
Index to sequences with linear recurrences with constant coefficients, signature (5,-10,10,-5,1)
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FORMULA
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G.f. -x*(9+19*x-5*x^2+x^3) /(x-1)^5 . - R. J. Mathar, Apr 02 2011
Using four consecutive triangular numbers t1, t2, t3, t4, form a 2x2 determinant with the first row t1 and t2 and the second row t3 and t4. Squaring the determinant gives the numbers in this sequence. - J. M. Bergot, May 17 2012
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MAPLE
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A099761 := proc(n) n^2*(n+2)^2 ; end proc:
seq(A099761(n), n=0..20) ; # R. J. Mathar, Apr 02 2011
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MATHEMATICA
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Table[(1 - 2 a^2 + a^4), {a, 1, 100}] - Artur Jasinski, Aug 15 2007
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CROSSREFS
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Sequence in context: A050792 A171671 A016886 * A092396 A018201 A181888
Adjacent sequences: A099758 A099759 A099760 * A099762 A099763 A099764
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KEYWORD
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easy,nonn
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AUTHOR
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Kari Lajunen (Kari.Lajunen(AT)Welho.com), Nov 11 2004
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EXTENSIONS
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Deleted a trivial formula which was based on another offset - R. J. Mathar, Dec 16 2009
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STATUS
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approved
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