A026219 Position of n in A026218.
1, 2, 5, 3, 9, 4, 13, 6, 17, 7, 21, 8, 25, 10, 29, 11, 33, 12, 37, 14, 41, 15, 45, 16, 49, 18, 53, 19, 57, 20, 61, 22, 65, 23, 69, 24, 73, 26, 77, 27, 81, 28, 85, 30, 89, 31, 93, 32, 97, 34, 101, 35, 105, 36, 109, 38, 113, 39, 117, 40, 121
Offset: 1
Keywords
Formula
Conjectures from Colin Barker, Oct 15 2019: (Start)
G.f.: x*(1 + 2*x + 4*x^2 + x^3 + 4*x^4 + x^5 + 3*x^6) / ((1 - x)^2*(1 + x)^2*(1 - x + x^2)*(1 + x + x^2)).
a(n) = a(n-2) + a(n-6) - a(n-8) for n>8.
(End)
Comments