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Search: id:A076465
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| A076465 |
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Sum of squares of numbers that can be written as t*n + u*(n+1) for nonnegative integers t,u in exactly n ways. |
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6
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| 1, 571, 12938, 115270, 630755, 2543401, 8307796, 23249388, 57792165, 130790935, 274285726, 540036146, 1008233863, 1798831685, 3085968040, 5116005976, 8229746121, 12889413363, 19711057330, 29503047070, 43311380651
(list; graph; listen)
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OFFSET
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1,2
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REFERENCES
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Fred. Schuh, Vragen betreffende een onbepaalde vergelijking, Nieuw Tijdschrift voor Wiskunde, 52 (1964-1965) 193-198.
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FORMULA
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1/6*n*(n+1)*(6*n^6+12*n^5-5*n^4-16*n^3+5*n+1). G.f.: x*(13*x^6+1354*x^5+11255*x^4+19300*x^3+7835*x^2+562*x+1)/((1+x)*(1-x)^9).
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MAPLE
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seq(1/6*n*(n+1)*(6*n^6+12*n^5-5*n^4-16*n^3+5*n+1), n=1..25);
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CROSSREFS
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Cf. A076389, A076459-A076464.
Sequence in context: A073036 A020381 A142767 this_sequence A144956 A049361 A090495
Adjacent sequences: A076462 A076463 A076464 this_sequence A076466 A076467 A076468
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KEYWORD
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easy,nonn
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AUTHOR
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Floor van Lamoen (fvlamoen(AT)hotmail.com), Oct 13 2002
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