A365199 a(n) is the index of the n-th occurrence of 1 in A365203.
1, 14, 53, 109, 221, 445, 893, 1789, 3581, 7165, 14333, 28669, 84530, 295033, 830369, 1660741, 4755764, 10372048, 28287409, 56574821, 153253317, 323636916, 848150626, 2217511139, 6534867338, 20173498129, 40346996261, 120496984345
Offset: 1
Examples
a(1) = 1 since A365203(1) = 1 (1st occurrence of 1). a(2) = 14 since A365203(14) = 1 (2nd occurrence of 1). a(3) = 53 since A365203(53) = 1 (3rd occurrence of 1). a(4) = 109 since A365203(109) = 1 (4th occurrence of 1).
Links
- Chai Wah Wu, Table of n, a(n) for n = 1..31
Crossrefs
Cf. A365203.
Programs
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Maple
A365203 := proc(n) option remember; if n = 1 then 1; elif procname(n - 1) < n then procname(n - 1) + n; elif n = procname(n - 1) then n*n; elif irem(procname(n - 1), n) = 0 then procname(n - 1)/n; else procname(n - 1) - n; end if; end proc; A365199 := proc(n) if A365203(n) = 1 then n; end if; end proc; seq(A365199(n), n = 1 .. 200000000);
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Python
from itertools import count,islice def A365199_gen(): # generator of terms yield (a:=1) for n in count(2): if a
Extensions
a(22)-a(23) from Michel Marcus, Aug 28 2023
a(24)-a(28) from Chai Wah Wu, Sep 23 2023