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Search: id:A076464
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| A076464 |
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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 five ways. |
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+0
2
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| 145, 4567, 38570, 183670, 630755, 1751365, 4187092, 8957100, 17583765, 32236435, 55893310, 92521442, 147274855, 226710785, 339024040, 494299480, 704782617, 985168335, 1352907730, 1828533070, 2436000875, 3203053117
(list; graph; listen)
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OFFSET
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1,1
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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)*(151*n^4+242*n^3+66*n^2-25*n+1). G.f.: x*(265*x^4+4512*x^3+9646*x^2+3552*x+145)/((1+x)*(1-x)^7).
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MAPLE
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seq(1/6*n*(n+1)*(151*n^4+242*n^3+66*n^2-25*n+1), n=1..30);
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CROSSREFS
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Cf. A076389, A076460-A076465.
Sequence in context: A031702 A031600 A008377 this_sequence A012813 A018232 A097730
Adjacent sequences: A076461 A076462 A076463 this_sequence A076465 A076466 A076467
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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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