A081851 Consider recurrence b(0) = (2n+1)/4, b(n) = b(0)*ceiling(b(n-1)); sequence gives first integer reached (or -1 if no integer is ever reached).

5, 7, 36, 1711985, 13, 15, 1700, 114, 168, 42000323, 275, 324, 58, 62, 23658393, 6055, 58311963, 9321, 121770, 13760, 135, 141, 1960, 344148, 5734229, 3391007266515, 8825709, 23546737390632357, 244, 252, 1526332099115586230, 105432399233, 27538521, 5680

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, A081850.

Programs

Maple

g:= proc(n) local b0, b, count;
  b0:= (2*n+1)/4; b:= b0;
  for count from 1 do
    b:= b0 * ceil(b);
    if b::integer then return b fi
  od
end proc:
map(g, [$2..100]); # Robert Israel, Sep 21 2018