A114969 Repeatedly divide by k, add d: k=2, d=5 case.

74, 37, 42, 21, 26, 13, 18, 9, 14, 7, 12, 6, 11

Offset

1,1

Comments

The next terms are non-integer: 11/2,21/2,21/4,41/4,41/8,81/8,81/16,161/16,... Independently on the initial term, the terms get closer and closer to the limit cycle a(n) = d*k/(k-1), a(n+1) = a(n)/2, a(n+2) = a(n+1)+d = a(n); in this case 10,5,10. Inspired by A112876.

Links

Table of n, a(n) for n=1..13.

Formula

From Chai Wah Wu, Sep 11 2018: (Start)

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

G.f.: -x*(x + 2)*(69*x^2 - 74)/(x^4 - 3*x^2 + 2). (End)

Crossrefs

Cf. A112876.

Sequence in context: A289853 A000319 A033394 * A104421 A352382 A136948

Adjacent sequences: A114966 A114967 A114968 * A114970 A114971 A114972

Keyword

nonn

Author

Zak Seidov, Feb 22 2006

Status

approved