A026044 a(n) = (d(n)-r(n))/2, where d = A026043 and r is the periodic sequence with fundamental period (1,1,0,0).

22, 33, 49, 70, 97, 132, 176, 229, 292, 367, 455, 556, 671, 802, 950, 1115, 1298, 1501, 1725, 1970, 2237, 2528, 2844, 3185, 3552, 3947, 4371, 4824, 5307, 5822, 6370, 6951, 7566, 8217, 8905, 9630, 10393, 11196, 12040, 12925, 13852, 14823, 15839, 16900, 18007, 19162, 20366, 21619, 22922, 24277

Offset: 5

Author

Clark Kimberling

Keywords

• nonn

Links

• Index entries for linear recurrences with constant coefficients, signature (4,-7,8,-7,4,-1).

Programs

Mathematica

LinearRecurrence[{4,-7,8,-7,4,-1},{22,33,49,70,97,132},60] (* Harvey P. Dale, Apr 27 2019 *)

Formula

a(n)=(n + 5)*(2*n^2 + 11*n + 54)/12 - 1/4 - (1/4)*cos(Pi*n/2) - (1/4)*sin(Pi*n/2) [From Richard Choulet, Dec 13 2008]

G.f. x^5*( 22-55*x+71*x^2-71*x^3+50*x^4-15*x^5 ) / ( (x^2+1)*(x-1)^4 ). - R. J. Mathar, Jun 22 2013