A226368 Numbers k such that Omega(k) = Omega(2^k + 1), where Omega = A001222 is the number of prime factors counted with multiplicity.

2, 6, 36, 44, 52, 60, 72, 88, 112, 116, 136, 140, 152, 184, 288, 292, 320, 352, 388, 400, 404, 536, 544, 584, 632, 796, 844, 928, 1072, 1136

Offset

1,1

Comments

At the moment, the least candidate for a(31) is 1168 = 2^4 * 73; the entry for 2^1168 + 1 on factordb.com has 3 prime factors and 1 composite cofactor with 326 decimal digits. - Lucas A. Brown, Mar 19 2024

Links

Table of n, a(n) for n=1..30.

Formula

{k: A054992(k) = A001222(k)}.

Prog

(PARI) is(n)=bigomega(2^n+1)==bigomega(n) \\ Charles R Greathouse IV, Mar 18 2014

Crossrefs

Cf. A001222, A054992, A155900.

Sequence in context: A324577 A324582 A275600 * A058083 A034526 A120824

Adjacent sequences: A226365 A226366 A226367 * A226369 A226370 A226371

Keyword

nonn,more,hard

Author

Irina Gerasimova, Jun 05 2013

Extensions

More terms from Jon E. Schoenfield, Sep 01 2013

a(29) added using factordb.com by Daniel Suteu, Jan 21 2023

a(30) added using factordb.com by Lucas A. Brown, Mar 19 2024

Status

approved