A339910 After 1, numbers k > 1 such that k has fewer prime divisors than k-1, when they are counted with multiplicity.

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.

Links

Antti Karttunen, Table of n, a(n) for n = 1..28208; all terms <= 65537

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

Adjacent sequences: A339907 A339908 A339909 * A339911 A339912 A339913

Keyword

nonn

Author

Antti Karttunen, Dec 22 2020

Status

approved