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0, 0, 2, 12, 39, 95, 195, 357, 602, 954, 1440, 2090, 2937, 4017, 5369, 7035, 9060, 11492, 14382, 17784, 21755, 26355, 31647, 37697, 44574, 52350, 61100, 70902, 81837, 93989, 107445, 122295, 138632, 156552, 176154, 197540, 220815, 246087
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OFFSET
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0,3
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COMMENTS
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The sequence 2 12 39 95 195 ... can be decomposed as 1 5 14 30 55 ... A000330 plus 1 7 25 65 140 ... A001296. - Alford Arnold, Jun 29 2005
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LINKS
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Table of n, a(n) for n=0..37.
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FORMULA
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a(n)=3*C(n+4,4)-C(n+2,2), n>= -2 . - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), May 02 2007
a(n)= 5*a(n-1) -10*a(n-2)+10*a(n-3) -5*a(n-4) +a(n-5) = n*(n-1)*(n^2+3*n-2)/8. G.f.: x^2*(-2-2*x+x^2)/(x-1)^5. [From R. J. Mathar, Oct 30 2009]
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EXAMPLE
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a(3)=t(t(3))-3^2=t(6)-9=21-9=12
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MAPLE
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seq(3*binomial(n+4, 4)-binomial(n+2, 2), n=-2..35); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), May 02 2007
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PROG
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(PARI) t(i)=i*(i+1)/2 w=vector(40, i, t(t(i))-i^2)
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CROSSREFS
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Cf. A000330, A001296.
Sequence in context: A048349 A009632 A190022 * A019006 A168057 A008911
Adjacent sequences: A086599 A086600 A086601 * A086603 A086604 A086605
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KEYWORD
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nonn
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AUTHOR
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Jon Perry, Jul 23 2003
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STATUS
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approved
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