A026067 a(n) = (d(n)-r(n))/2, where d = A026066 and r is the periodic sequence with fundamental period (1,0,0,0).

52, 84, 123, 170, 225, 290, 364, 448, 542, 648, 765, 894, 1035, 1190, 1358, 1540, 1736, 1948, 2175, 2418, 2677, 2954, 3248, 3560, 3890, 4240, 4609, 4998, 5407, 5838, 6290, 6764, 7260, 7780, 8323, 8890, 9481, 10098, 10740, 11408, 12102, 12824, 13573, 14350, 15155, 15990, 16854

Offset: 7

Author

Clark Kimberling

Keywords

• nonn
• easy

Links

• Index entries for linear recurrences with constant coefficients, signature (3,-3,1,1,-3,3,-1).

Crossrefs

Cf. A026066.

Formula

G.f.: x^7*( 52-72*x+27*x^2+x^3+74*x^5-28*x^6-52*x^4 ) / ( (1+x)*(x^2+1)*(x-1)^4 ). - R. J. Mathar, Jun 23 2013