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A360117
Numbers k such that for all their prime factors p, v(p-1) <= v(k-1), where v(n) = A007814(n) is the 2-adic valuation of n.
3
2, 3, 4, 5, 7, 8, 9, 11, 13, 16, 17, 19, 21, 23, 25, 27, 29, 31, 32, 33, 37, 41, 43, 45, 47, 49, 53, 57, 59, 61, 63, 64, 65, 67, 69, 71, 73, 77, 79, 81, 83, 89, 93, 97, 99, 101, 103, 105, 107, 109, 113, 117, 121, 125, 127, 128, 129, 131, 133, 137, 139, 141, 145, 147, 149, 151, 157, 161, 163, 165, 167
OFFSET
1,1
MATHEMATICA
q[n_] := Module[{v = IntegerExponent[n - 1, 2]}, AllTrue[FactorInteger[n][[;; , 1]], IntegerExponent[# - 1, 2] <= v &]]; Select[Range[2, 200], q] (* Amiram Eldar, Feb 10 2023 *)
PROG
(PARI) isA360117(n) = A360116(n);
CROSSREFS
Union of A000040, A000079 \ {1} and A345330 (odd composite terms).
Cf. A007814, A360116 (characteristic function).
Sequence in context: A344979 A273130 A273200 * A014567 A324769 A328867
KEYWORD
nonn
AUTHOR
Antti Karttunen, Feb 10 2023
STATUS
approved