A390234 Numbers k such that sigma(k) = psi(k) + pi(k) + omega(k).

1, 16, 124, 162, 891, 22938350, 215035725, 401022525

Offset

1,2

Links

Table of n, a(n) for n=1..8.

Example

16 is a term since sigma(16) = 31 = 24 + 6 + 1 = psi(16) + pi(16) + omega(16).

Prog

(PARI) dedpsi(f) = prod(k = 1, #f~, (f[k, 1]+1) * f[k, 1]^(f[k, 2]-1));
list(lim) = {my(q = 2, m = 0, f); print1(1, ", "); forprime(p = 3, lim, m++; for(k = q, p-1, f = factor(k); if(sigma(f) == dedpsi(f) + m + omega(f), print1(k, ", "))); q = p); } \\ Amiram Eldar, Jan 20 2026

Crossrefs

Cf. A000203, A000720, A001615, A001221.

Sequence in context: A006215 A227088 A060633 * A125353 A126511 A231582

Adjacent sequences: A390231 A390232 A390233 * A390235 A390236 A390237

Keyword

nonn,hard,more

Author

S. I. Dimitrov, Jan 20 2026

Extensions

a(7)-a(8) from Amiram Eldar, Jan 20 2026

Status

approved