A306401 The smallest integer k | 2^k + 1 such that omega(k) = n.

1, 3, 171, 97641, 143239347, 626958621819, 5519116747872657, 50428169725312467009, 2073253341916771456141017, 163345411049596672714982306379, 14245516643046375424146321921618969, 1929313055517699762818408816810621828577, 269106372922775316017200116995195964515405691, 38930811651619136642260289325344014598550195099897

Offset

0,2

Comments

Conjecture: a(n) | a(n+1).

Conjecture does not hold in general and first time fails at n=26, then it fails at n=47, n=72, and so on. - Max Alekseyev, Oct 12 2023

Links

Max Alekseyev, Table of n, a(n) for n = 0..100

Prog

(PARI) v = readvec("v006521.txt");
a(n) = {k=1; while(omega(v[k]) != n, k++); v[k]; };
(PARI) a(n) = my(m=1); while((Mod(2, m)^m!=-1) || (omega(m)!=n), m++); m; \\ Michel Marcus, Feb 16 2019

Crossrefs

Cf. A006521, A001221 (omega).

Sequence in context: A119117 A136473 A209804 * A053930 A053920 A297948

Adjacent sequences: A306398 A306399 A306400 * A306402 A306403 A306404

Keyword

nonn

Author

Jinyuan Wang, Feb 15 2019

Extensions

a(6)-a(10) confirmed, terms (11) onward added by Max Alekseyev, Oct 12 2023

Status

approved