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Search: id:A107247
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| A107247 |
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Sum of squares of nonacci numbers (Fibonacci 9-step numbers). |
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+0
2
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| 0, 0, 0, 0, 0, 0, 0, 1, 2, 6, 22, 86, 342, 1366, 5462, 21846, 87382, 348503, 1390944, 5552544, 22166320, 88491056, 353269040, 1410299184, 5630100784, 22476064048, 89727075632, 358201316657, 1429983219018, 5708667195022, 22789694921422
(list; graph; listen)
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OFFSET
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0,9
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COMMENT
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Primes in this sequence include: a(9) = 2, which is next? Semiprimes in this sequence include: a(10) = 6 = 2 * 3, a(11) = 22 = 2 * 11, a(12) = 86 = 2 * 43, a(14) = 1366 = 2 * 683, a(15) = 5462 = 2 * 2731, a(17) = 87382 = 2 * 43691, a(18) = 348503 = 37 * 9419, a(28) = 358201316657 = 71 * 5045088967.
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LINKS
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Eric Weisstein's World of Mathematics, Fibonacci n-Step Number.
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FORMULA
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a(n) = F_9(0)^2 + F_9(1)^2 + ... F_9(n)^2, where F_9(n) = A104144(n).
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CROSSREFS
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Cf. A104144, A107239-A107246, A107248.
Sequence in context: A107243 A107244 A107246 this_sequence A047849 A107245 A150256
Adjacent sequences: A107244 A107245 A107246 this_sequence A107248 A107249 A107250
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KEYWORD
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easy,nonn
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AUTHOR
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Jonathan Vos Post (jvospost3(AT)gmail.com), May 29 2005
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