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Search: id:A063978
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| A063978 |
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Sum_{i for which n - i*(i-1)/2 >= 0} binomial (n - i*(i-1)/2, i). |
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+0
2
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| 1, 2, 3, 5, 8, 12, 18, 27, 40, 58, 83, 118, 167, 235, 328, 454, 624, 853, 1161, 1574, 2125, 2856, 3821, 5090, 6754, 8931, 11773, 15474, 20280, 26502, 34533, 44870, 58142, 75145, 96885, 124630, 159973, 204909, 261930, 334143, 425417, 540566
(list; graph; listen)
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OFFSET
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0,2
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FORMULA
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G.f.: Sum(x^(k*(k-1)/2)/(1-x)^k, k=1..infinity). - Vladeta Jovovic (vladeta(AT)eunet.rs), Sep 25 2004
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MATHEMATICA
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Table[ Sum[ Binomial[ n - i(i - 1)/2, i], {i, 0, Floor[ (Sqrt[8n + 1] - 1)/2]} ], {n, 0, 40}]
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CROSSREFS
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Cf. A064188.
Sequence in context: A007478 A014605 A132842 this_sequence A077868 A109537 A081226
Adjacent sequences: A063975 A063976 A063977 this_sequence A063979 A063980 A063981
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KEYWORD
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nonn
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AUTHOR
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Helmut Schnitzspan (HSchnitzspan(AT)gmx.de), Sep 05 2001
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EXTENSIONS
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More terms from Dean Hickerson, Sep 06 2001
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