A387710 Numbers k for which A003959(k) < 2*k, where A003959 is multiplicative with a(p^e) = (p+1)^e.

1, 2, 3, 5, 7, 9, 10, 11, 13, 14, 15, 17, 19, 21, 22, 23, 25, 26, 29, 31, 33, 34, 35, 37, 38, 39, 41, 43, 46, 47, 49, 51, 53, 55, 57, 58, 59, 61, 62, 65, 67, 69, 71, 73, 74, 75, 77, 79, 82, 83, 85, 86, 87, 89, 91, 93, 94, 95, 97, 98, 99, 101, 103, 105, 106, 107, 109, 110, 111, 113, 115, 117, 118, 119, 121, 122, 123, 125

Offset: 1

Author

Antti Karttunen, Sep 06 2025

Keywords

• nonn
• new

Links

• Antti Karttunen, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A003959, A387711.

Subsequence of A005100.

Subsequences: A000040, A001358\{4, 6}, A246281.

Positions of 0's in A387715.

Programs

PARI

A003959(n) = { my(f = factor(n)); for(i=1, #f~, f[i, 1]++); factorback(f); };
is_A387710(n) = (A003959(n)<(2*n));