login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Limiting sequence when we start with positive integers (A000027) and at step n >= 1 add to the term at position n + a(n) the value a(n) if the term is odd, else divide the term by 2.
1

%I #17 Feb 27 2024 03:04:25

%S 1,1,4,4,5,6,11,4,9,5,11,3,13,14,10,16,17,18,19,20,21,11,23,24,35,13,

%T 27,14,29,30,31,16,44,17,35,18,37,19,52,20,41,35,43,44,45,23,47,12,49,

%U 50,68,52,53,45,55,56,76,29,59,47,61,31,63,64,65,66,67,68,92,35

%N Limiting sequence when we start with positive integers (A000027) and at step n >= 1 add to the term at position n + a(n) the value a(n) if the term is odd, else divide the term by 2.

%o (PARI) lista(nn) = my(va = [1..nn]); for (n=1, nn, my(m = n+va[n]); if (m <= nn, if (va[m] % 2, va[m]+=va[n], va[m] /= 2));); va; \\ _Michel Marcus_, Oct 29 2022

%Y Cf. A000027, A136119, A137319, A137417, A137418, A136259, A136272, A137901, A137902.

%K easy,nonn

%O 1,3

%A _Ctibor O. Zizka_, Apr 30 2008

%E Entries corrected and extended by _Paolo P. Lava_, Mar 10 2009

%E More terms from _Michel Marcus_, Oct 29 2022