A387713 Nonprimitive terms of A387711: numbers k for which A387715(k) > 1.

8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52, 54, 56, 60, 64, 68, 72, 76, 80, 81, 84, 88, 90, 92, 96, 100, 104, 108, 112, 116, 120, 124, 126, 128, 132, 135, 136, 140, 144, 148, 150, 152, 156, 160, 162, 164, 168, 172, 176, 180, 184, 188, 189, 192, 196, 198, 200, 204, 208, 210, 212, 216, 220, 224, 225, 228, 232, 234

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.

Setwise difference A387711 \ A387712. Positions of terms > 1 in A387715.

Subsequence of A341610.

Programs

PARI

A003959(n) = { my(f = factor(n)); for(i=1, #f~, f[i, 1]++); factorback(f); };
A387715(n) = sumdiv(n,d,(A003959(d)>(2*d)));
is_A387713(n) = (A387715(n)>1);

Formula

{k | A387715(k) > 1}.