A147677 Subtract 5, add 8, repeat.

7, 2, 10, 5, 13, 8, 16, 11, 19, 14, 22, 17, 25, 20, 28, 23, 31, 26, 34, 29, 37, 32, 40, 35, 43, 38, 46, 41, 49, 44, 52, 47, 55, 50, 58, 53, 61, 56, 64, 59, 67, 62, 70, 65, 73, 68, 76, 71, 79, 74, 82, 77, 85, 80, 88, 83, 91, 86, 94, 89, 97, 92, 100, 95, 103, 98, 106, 101, 109

Offset

1,1

Comments

A147675, A147676, this sequence, and A147678, are from a quiz that someone asked me to help them with.

Links

G. C. Greubel, Table of n, a(n) for n = 1..1000

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

Formula

From Zak Seidov, Apr 22 2009: (Start)

a(n) = a(n-2) + 3.

a(n) = (1/4)*(6*n + 9 - 13*(-1)^n). (End)

From R. J. Mathar, Apr 22 2009: (Start)

a(n) = a(n-1) + a(n-2) - a(n-3).

G.f.: x*(7-5*x+x^2)/((1+x)*(1-x)^2). (End)

E.g.f.: (1/2)*( (11+3*x)*sinh(x) - (2-3*x)*cosh(x) + 2). - G. C. Greubel, Dec 02 2025

Mathematica

LinearRecurrence[{1, 1, -1}, {7, 2, 10}, 80] (* Harvey P. Dale, Jan 16 2015 *)

Prog

(Magma)
A147677:= func< n | (3*n-2 +13*(n mod 2))/2 >;
[A147677(n): n in [1..80]]; // G. C. Greubel, Dec 02 2025
(SageMath)
def A147677(n): return ( 3*n-2 + 13*(n%2) )//2
print([A147677(n) for n in range(1, 81)]) # G. C. Greubel, Dec 02 2025

Crossrefs

Cf. A147675, A147676, A147678.

Sequence in context: A246948 A364899 A248283 * A090243 A216150 A145338

Adjacent sequences: A147674 A147675 A147676 * A147678 A147679 A147680

Keyword

nonn,easy

Author

N. J. A. Sloane, Apr 21 2009

Extensions

More terms from Zak Seidov and R. J. Mathar, Apr 22 2009

Status

approved