A026064 a(n) = (d(n)-r(n))/2, where d = A026063 and r is the periodic sequence with fundamental period (1,1,0,1).

35, 59, 90, 127, 172, 225, 287, 357, 437, 527, 628, 739, 862, 997, 1145, 1305, 1479, 1667, 1870, 2087, 2320, 2569, 2835, 3117, 3417, 3735, 4072, 4427, 4802, 5197, 5613, 6049, 6507, 6987, 7490, 8015, 8564, 9137, 9735, 10357, 11005, 11679, 12380, 13107, 13862, 14645, 15457, 16297

Offset: 6

Author

Clark Kimberling

Keywords

• nonn
• easy

Links

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

Formula

a(n)=(n + 6)*(n^2 + 30*n + 71)/12 - 0.375 + 0.125*( - 1)^n - 0.25*cos(n*Pi/2) [From Richard Choulet, Dec 13 2008]

G.f.: x^6*( 35-46*x+18*x^2-x^3-33*x^4-17*x^6+46*x^5 ) / ( (1+x)*(x^2+1)*(x-1)^4 ). - R. J. Mathar, Jun 23 2013