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A017246
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a(n) = (9*n + 7)^2.
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2
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49, 256, 625, 1156, 1849, 2704, 3721, 4900, 6241, 7744, 9409, 11236, 13225, 15376, 17689, 20164, 22801, 25600, 28561, 31684, 34969, 38416, 42025, 45796, 49729, 53824, 58081, 62500, 67081, 71824
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OFFSET
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0,1
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LINKS
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FORMULA
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a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3); a(0)=49, a(1)=256, a(2)=625. - Harvey P. Dale, Apr 24 2016
G.f.: -(49 + 109*x + 4*x^2)/(x-1)^3. - R. J. Mathar, Mar 20 2018
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MATHEMATICA
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(9*Range[0, 30]+7)^2 (* or *) LinearRecurrence[{3, -3, 1}, {49, 256, 625}, 30] (* Harvey P. Dale, Apr 24 2016 *)
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PROG
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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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