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A354925 Union of powers of primes and even semiprimes. 1
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14, 16, 17, 19, 22, 23, 25, 26, 27, 29, 31, 32, 34, 37, 38, 41, 43, 46, 47, 49, 53, 58, 59, 61, 62, 64, 67, 71, 73, 74, 79, 81, 82, 83, 86, 89, 94, 97, 101, 103, 106, 107, 109, 113, 118, 121, 122, 125, 127, 128, 131, 134, 137, 139, 142, 146, 149, 151, 157, 158, 163, 166, 167, 169 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
MATHEMATICA
Join[{1}, Select[Range[170], PrimePowerQ[#] || PrimeQ[#/2] &]] (* Amiram Eldar, Jun 13 2022 *)
PROG
(PARI)
A354923(n) = ((1==n)|| isprimepower(n) || (!(n%2) && isprime(n/2)));
isA354925(n) = A354923(n);
CROSSREFS
Union of A000961 and A100484.
Apart from {1}, complement of A265128.
Cf. A354923 (characteristic function).
Sequence in context: A195044 A033112 A049813 * A362184 A368904 A229991
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jun 13 2022
STATUS
approved

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Last modified February 22 02:45 EST 2024. Contains 370239 sequences. (Running on oeis4.)