A328320 Numbers for which A328311(n) = 1 + A051903(A003415(n)) - A051903(n) is zero (including 1 as the initial term).

1, 2, 3, 5, 7, 8, 9, 11, 13, 17, 18, 19, 23, 24, 25, 29, 31, 32, 37, 40, 41, 43, 45, 47, 49, 53, 56, 59, 61, 63, 67, 71, 72, 73, 75, 79, 81, 83, 88, 89, 90, 96, 97, 98, 101, 103, 104, 107, 109, 113, 117, 120, 121, 125, 126, 127, 128, 131, 136, 137, 139, 147, 149, 150, 151, 152, 153, 157, 160, 162, 163, 167, 168, 169

Offset

1,2

Comments

After 1, the numbers whose "degree" (maximal exponent, A051903) is decremented by one when arithmetic derivative (A003415) is applied to them.

Links

Antti Karttunen, Table of n, a(n) for n = 1..20000

Prog

(PARI)
A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
A051903(n) = if((1==n), 0, vecmax(factor(n)[, 2]));
A328311(n) = if(n<=1, 0, 1+(A051903(A003415(n)) - A051903(n)));
isA328320(n) = (0==A328311(n));

Crossrefs

Cf. A003415, A051903, A328302, A328310.

Indices of zeros in A328311.

Cf. A328321 (complement), A328252 (a subsequence).

Sequence in context: A353968 A144100 A359059 * A086539 A171217 A344591

Adjacent sequences: A328317 A328318 A328319 * A328321 A328322 A328323

Keyword

nonn

Author

Antti Karttunen, Oct 13 2019

Status

approved