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A071237
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a(n) = n*(n+1)*(n^2+1)/2.
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4
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0, 2, 15, 60, 170, 390, 777, 1400, 2340, 3690, 5555, 8052, 11310, 15470, 20685, 27120, 34952, 44370, 55575, 68780, 84210, 102102, 122705, 146280, 173100, 203450, 237627, 275940, 318710, 366270, 418965, 477152, 541200, 611490, 688415, 772380, 863802, 963110
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OFFSET
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0,2
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REFERENCES
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T. A. Gulliver, Sequences from Arrays of Integers, Int. Math. Journal, Vol. 1, No. 4, pp. 323-332, 2002.
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LINKS
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FORMULA
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a(0) = 0, a(1) = 2; for n >= 2, a(n) = ceiling(n^5/(2*n-2)) - 1.
G.f.: x*(2 + 5*x*(1 + x))/(1 - x)^5. (End)
a(n) = 5*a(n-1) -10*a(n-2) +10*a(n-3) -5*a(n-4) +a(n-5) for n>4, a(0)=0, a(1)=2, a(2)=15, a(3)=60, a(4)=170. - Yosu Yurramendi, Sep 03 2013
E.g.f.: (1/2)*x*(4 + 11*x + 7*x^2 + x^3)*exp(x). - G. C. Greubel, Aug 05 2024
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MATHEMATICA
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PROG
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(SageMath)
def A071237(n): return (n^2+1)*binomial(n+1, 2)
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CROSSREFS
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KEYWORD
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nonn,easy,changed
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AUTHOR
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STATUS
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approved
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