A354929 Numbers of the form 2*p^e, with p an odd prime and e >= 2.

18, 50, 54, 98, 162, 242, 250, 338, 486, 578, 686, 722, 1058, 1250, 1458, 1682, 1922, 2662, 2738, 3362, 3698, 4374, 4394, 4418, 4802, 5618, 6250, 6962, 7442, 8978, 9826, 10082, 10658, 12482, 13122, 13718, 13778, 15842, 18818, 20402, 21218, 22898, 23762, 24334, 25538, 29282, 31250, 32258

Offset: 1

Author

Antti Karttunen, Jun 13 2022

Keywords

• nonn

Comments

Conjecturally numbers k > 1 such that A047994(k) = A344005(k) (see A354928), and k is in A265128. See comments in A346608.

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Subsequence of A278568.

Intersection of A265128 and A354928 (conjectured).

Cf. A047994, A136141, A344005, A346608, A354924.

Programs

Mathematica

Select[Range[33000], IntegerExponent[#, 2] == 1 && CompositeQ[#/2] && PrimePowerQ[#/2] &] (* Amiram Eldar, Jun 18 2022 *)

PARI

isA354929(n) = ((2==(n%4)) && (isprimepower(n/2)>1));

Formula

Sum_{n>=1} 1/a(n) = (A136141 - 1/2)/2 = 0.1365783345... - Amiram Eldar, Jun 18 2022