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A107247 Sum of squares of nonacci numbers (Fibonacci 9-step numbers). 6
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; refs; listen; history; text; internal format)
OFFSET

0,9

COMMENTS

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.

LINKS

Table of n, a(n) for n=0..30.

Eric Weisstein's World of Mathematics, Fibonacci n-Step Number.

Index entries for linear recurrences with constant coefficients, signature (3, 2, 4, 8, 15, 31, 62, 124, 248, -522, -24, -38, -32, 120, -26, -68, -138, -160, 392, 16, 30, 22, -68, 0, 16, 50, 58, -124, 0, -6, -8, 14, 0, 0, -6, -12, 18, 0, 0, 1, -1, 0, 0, 0, 1, -1).

FORMULA

a(n) = F_9(0)^2 + F_9(1)^2 + ... F_9(n)^2, where F_9(n) = A104144(n).

MATHEMATICA

Accumulate[LinearRecurrence[{1, 1, 1, 1, 1, 1, 1, 1, 1}, {0, 0, 0, 0, 0, 0, 0, 0, 1}, 31]^2]  (* Ray Chandler, Aug 02 2015 *)

CROSSREFS

Cf. A104144, A107239-A107246, A107248.

Sequence in context: A107244 A107245 A107246 * A047849 A277222 A150256

Adjacent sequences:  A107244 A107245 A107246 * A107248 A107249 A107250

KEYWORD

easy,nonn

AUTHOR

Jonathan Vos Post, May 29 2005

STATUS

approved

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Last modified October 1 14:12 EDT 2022. Contains 357149 sequences. (Running on oeis4.)