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A262140
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The first of nine consecutive positive integers the sum of the squares of which is equal to the sum of the squares of eight consecutive positive integers.
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2
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20, 136, 812, 4752, 27716, 161560, 941660, 5488416, 31988852, 186444712, 1086679436, 6333631920, 36915112100, 215157040696, 1254027132092, 7309005751872, 42600007379156, 248291038523080, 1447146223759340, 8434586304032976, 49160371600438532
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OFFSET
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1,1
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COMMENTS
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For the first of the corresponding eight consecutive positive integers, see A262139.
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LINKS
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FORMULA
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a(n) = 7*a(n-1)-7*a(n-2)+a(n-3) for n>3.
G.f.: 4*x*(x-5) / ((x-1)*(x^2-6*x+1)).
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EXAMPLE
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20 is in the sequence because 20^2 + ... + 28^2 = 5244 = 22^2 + ... + 29^2.
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PROG
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(PARI) Vec(4*x*(x-5)/((x-1)*(x^2-6*x+1)) + O(x^40))
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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