A336549 Numbers k, not powers of primes, such that A051027(k) = Product_{p^e|k} A051027(p^e). Here each p^e is the maximal power of prime p that divides k, and A051027(k) = sigma(sigma(k)).

6, 12, 14, 18, 20, 24, 26, 28, 36, 38, 44, 45, 48, 50, 54, 56, 62, 63, 68, 72, 74, 75, 76, 80, 86, 92, 96, 99, 100, 104, 108, 112, 116, 117, 122, 124, 126, 134, 144, 146, 147, 148, 150, 153, 158, 162, 171, 172, 175, 176, 180, 188, 192, 194, 196, 200, 206, 207, 208, 212, 218, 224, 225, 234, 236, 242, 244, 248, 252, 254

Offset: 1

Author

Antti Karttunen, Jul 25 2020

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..25000
• Index entries for sequences related to sigma(n)

Crossrefs

Terms of A336547 without A000961.

Cf. A051027, A336546, A336548.

Subsequence of A336559. Cf also A336560.

Programs

PARI

isA336549(n) = ((n>1) && !isprimepower(n) && A336546(n)); \\ Needs also code from A336546.