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A339910
After 1, numbers k > 1 such that k has fewer prime divisors than k-1, when they are counted with multiplicity.
5
1, 5, 7, 9, 11, 13, 17, 19, 21, 23, 25, 29, 31, 33, 37, 41, 43, 46, 47, 49, 51, 53, 55, 57, 59, 61, 65, 67, 69, 71, 73, 77, 79, 81, 82, 83, 85, 89, 91, 93, 97, 101, 103, 105, 106, 107, 109, 111, 113, 115, 118, 121, 127, 129, 131, 133, 137, 139, 141, 145, 149, 151, 153, 155, 157, 161, 163, 166, 167, 169, 173, 177, 179
OFFSET
1,2
COMMENTS
List of starts of nondecreasing runs of values of A001222 (= bigomega, number of prime factors, when counted with multiplicity).
Differs from A303578 (a similar sequence computed for tau, the number of divisors) for the first time at n=44, where a(44) = 105, a term missing from A303578.
MATHEMATICA
1 + {0}~Join~Position[Sign@ Differences[Array[PrimeOmega, 180]], -1][[All, 1]] (* Michael De Vlieger, Dec 22 2020 *)
PROG
(PARI) isA339910(n) = ((1==n)||(bigomega(n)<bigomega(n-1)));
CROSSREFS
Cf. A001222.
One more than A322839.
Cf. A339911, A339912 for subsequences.
Cf. also A303578.
Sequence in context: A035034 A065155 A230203 * A303578 A282057 A336366
KEYWORD
nonn
AUTHOR
Antti Karttunen, Dec 22 2020
STATUS
approved