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Search: id:A076454
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| A076454 |
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Sum of numbers that can be written as t*n + u*(n+1) for nonnegative integers t,u in exactly one way. |
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+0
6
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| 1, 21, 102, 310, 735, 1491, 2716, 4572, 7245, 10945, 15906, 22386, 30667, 41055, 53880, 69496, 88281, 110637, 136990, 167790, 203511, 244651, 291732, 345300, 405925, 474201, 550746, 636202, 731235, 836535, 952816, 1080816, 1221297
(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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1/2*n*(n+1)*(2*n^2-1). G.f.: x*(7*x^2+16*x+1)/((1+x)*(1-x)^5).
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MAPLE
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seq(1/2*n*(n+1)*(2*n^2-1), n=1..40);
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CROSSREFS
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Cf. A002417, A076455-A076459.
Sequence in context: A126408 A044272 A044653 this_sequence A069499 A068142 A126229
Adjacent sequences: A076451 A076452 A076453 this_sequence A076455 A076456 A076457
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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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