A081850 Consider recurrence b(0) = (2n+1)/4, b(n) = b(0)*ceiling(b(n-1)); sequence gives number of steps to reach an integer (or -1 if no integer is ever reached).

3, 2, 3, 13, 1, 1, 4, 2, 2, 9, 2, 2, 1, 1, 7, 3, 7, 3, 4, 3, 1, 1, 2, 4, 5, 10, 5, 13, 1, 1, 14, 8, 5, 2, 10, 11, 1, 1, 6, 2, 2, 17, 2, 2, 1, 1, 3, 6, 16, 5, 3, 4, 1, 1, 2, 4, 7, 9, 4, 3, 1, 1, 15, 9, 4, 2, 7, 5, 1, 1, 3, 2, 2, 3, 2, 2, 1, 1, 5, 5, 6, 5, 6, 4, 1, 1, 2, 4, 4, 3, 3, 11, 1, 1, 3, 3, 7, 2, 4

Offset: 2

Author

N. J. A. Sloane, Apr 13 2003

Keywords

• nonn

Links

• Robert Israel, Table of n, a(n) for n = 2..10000

Crossrefs

Cf. A073524, A081849, A081851.

Programs

Maple

Digits := 100: c := ceil; A081850 := proc(a) local i,t0,t; t0 := a; t := 0; for i from 1 to 100 do if whattype(t0) <> integer then t0 := a*c(t0); t := t+1; else RETURN(t); fi; od; RETURN('FAIL'); end;