A071886 -id:A071886 - cp's OEIS frontend

A071884 Trajectory of 37 under map x -> A002487(x)*A002487(x+1).

37, 77, 170, 714, 3450, 10414, 68145, 303610, 721305, 1815066, 17782782, 4598150, 68178460, 133118649, 585506070, 20663527908, 777507763200, 264506067126, 73112062114130, 5907184479605316, 516068243814152148

Offset: 0

N. J. A. Sloane and J. H. Conway, Jun 10 2002

nonn

All smaller starting values lead into a cycle after a small number of steps; this appears to have an infinite trajectory.

Cf. A002487, A071885, A071886, A071887.

# n is starting value, m is length of trajectory to compute
f := proc(n,m) local t1,i,j; t1 := [n]; for i from 2 to m do j := t1[i-1]; t1 := [op(t1), A002487(j)*A002487(j+1)]; od: t1; end;

A071885 Trajectory of 38 under map x -> A002487(x)*A002487(x+1).

Original entry on oeis.org

38, 70, 117, 198, 368, 210, 558, 1312, 693, 3920, 2438, 6900, 17138, 43792, 105939, 553150, 862695, 5466578, 262720694, 8088309190, 155799611901, 2918284055518, 415202250061643, 1166813484199476, 224311803609338424

Offset: 0