A392053 Numbers k such that sigma(k) = psi(k) + pi(k) + omega(k)^4.

1, 16, 2943, 3870, 24993, 50327950, 50330650, 346452825, 390696875, 401044425, 401045325

Offset

1,2

Links

Table of n, a(n) for n=1..11.

Example

2943 is a term since sigma(2943) = 4400 = 3960 + 424 + 2^4 = psi(2943) + pi(2943) + omega(2943)^4.

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)^4, print1(k, ", "))); q = p); } \\ Amiram Eldar, Jan 26 2026

Crossrefs

Cf. A000203, A000720, A001615, A001221, A390234, A390235, A390236.

Sequence in context: A374414 A123282 A091160 * A049030 A223068 A051551

Adjacent sequences: A392050 A392051 A392052 * A392054 A392055 A392056

Keyword

nonn,hard,more

Author

S. I. Dimitrov, Jan 26 2026

Extensions

a(8)-a(11) from Amiram Eldar, Jan 26 2026

Status

approved