A282738 First differences of A282737.

1, 2, 1, 4, 1, 5, 1, 6, 1, 7, 1, 8, 1, 9, 1, 10, 1, 11, 1, 12, 1, 13, 1, 14, 1, 15, 1, 16, 1, 17, 1, 18, 1, 19, 1, 20, 1, 21, 1, 22, 1, 23, 1, 24, 1, 25, 1, 26, 1, 27, 1, 28, 1, 29, 1, 30, 1, 31, 1, 32, 1, 33, 1, 34, 1, 35, 1, 36, 1, 37, 1, 38, 1, 39, 1, 40, 1, 41, 1

Offset: 0

Author

N. J. A. Sloane, Mar 04 2017

Keywords

• nonn
• easy

Links

• Colin Barker, Table of n, a(n) for n = 0..1000
• Index entries for linear recurrences with constant coefficients, signature (0,2,0,-1).

Crossrefs

Cf. A282737.

A152271 and A133622 are very similar sequences.

Programs

PARI

Vec((1 + 2*x - x^2 - x^5) / ((1 - x)^2*(1 + x)^2) + O(x^100)) \\ Colin Barker, Mar 04 2017

Formula

G.f.: (1 + 2*x - x^2 - x^5) / (1 - x^2)^2.

From Colin Barker, Mar 04 2017: (Start)

a(n) = 2*a(n-2) - a(n-4) for n>3.

a(n) = 1 for n>1 and even.

a(n) = (n+5) / 2 for n>1 and odd.

(End)