A107244 Sum of squares of hexanacci numbers (A001592, Fibonacci 6-step numbers).
0, 0, 0, 0, 0, 1, 2, 6, 22, 86, 342, 1366, 5335, 20960, 82464, 324528, 1277104, 5025200, 19770800, 77789489, 306071370, 1204272270, 4738336974, 18643463374, 73354544590, 288620849614, 1135607911375, 4468164041216, 17580442344960
Offset: 0
Examples
a(0) = 0 = 0^2 a(1) = 0 = 0^2 + 0^2 a(2) = 0 = 0^2 + 0^2 + 0^2 a(3) = 0 = 0^2 + 0^2 + 0^2 + 0^2 a(4) = 0 = 0^2 + 0^2 + 0^2 + 0^2 + 0^2 a(5) = 1 = 0^2 + 0^2 + 0^2 + 0^2 + 0^2 + 1^2 a(6) = 2 = 0^2 + 0^2 + 0^2 + 0^2 + 0^2 + 1^2 + 1^2 a(7) = 6 = 0^2 + 0^2 + 0^2 + 0^2 + 0^2 + 1^2 + 1^2 + 2^2 a(8) = 22 = 0^2 + 0^2 +0^2 + 0^2 + 0^2 + 1^2 + 1^2 + 2^2 + 4^2
Links
- Eric Weisstein's World of Mathematics, Fibonacci n-Step Number.
- Index entries for linear recurrences with constant coefficients, signature (3, 2, 4, 6, 14, 28, -67, -9, -8, 28, -8, -12, 20, 5, 5, -10, 0, 2, -2, 0, -1, 1).
Programs
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Mathematica
Accumulate[LinearRecurrence[{1,1,1,1,1,1},{0,0,0,0,0,1},50]^2] (* Harvey P. Dale, Jan 19 2012 *) LinearRecurrence[{3, 2, 4, 6, 14, 28, -67, -9, -8, 28, -8, -12, 20, 5, 5, -10, 0, 2, -2, 0, -1, 1},{0, 0, 0, 0, 0, 1, 2, 6, 22, 86, 342, 1366, 5335, 20960, 82464, 324528, 1277104, 5025200, 19770800, 77789489, 306071370, 1204272270},29] (* Ray Chandler, Aug 02 2015 *)
Formula
a(n) = F_6(0)^2 + F_6(1)^2 + ... F_6(n)^2, where F_6(n) = A001592(n). a(0) = 0, a(n+1) = a(n) + A001592(n).
a(n)= 3*a(n-1) +2*a(n-2) +4*a(n-3) +6*a(n-4) +14*a(n-5) +28*a(n-6) -67*a(n-7) -9*a(n-8) -8*a(n-9) +28*a(n-10) -8*a(n-11) -12*a(n-12) +20*a(n-13) +5*a(n-14) +5*a(n-15) -10*a(n-16) +2*a(n-18) -2*a(n-19) -a(n-21) +a(n-22). [From R. J. Mathar, Aug 11 2009]
Comments