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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)).
13
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
1,1
PROG
(PARI) isA336549(n) = ((n>1) && !isprimepower(n) && A336546(n)); \\ Needs also code from A336546.
CROSSREFS
Terms of A336547 without A000961.
Subsequence of A336559. Cf also A336560.
Sequence in context: A246048 A348251 A290648 * A136155 A315599 A136151
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jul 25 2020
STATUS
approved