A391448 Numbers k such that sigma(k) = psi(k) + phi(k) + Omega(k)^5.

43960, 60048, 93016, 108472, 179032, 212800, 227416, 323512, 323752, 340312, 345016, 363832, 367192, 1213256, 1727300, 43452064, 149350144, 578239744, 5420831744, 15012217856

Offset

1,1

Links

Table of n, a(n) for n=1..20.

Example

43960 is a term since sigma(43960) = 113760 = 91008 + 14976 + 6^5 = psi(43960) + phi(43960) + Omega(43960)^5.

Prog

(PARI) isok(k) = {my(f = factor(k)); sigma(f) == prod(i=1, #f~, (f[i, 1]+1) * f[i, 1]^(f[i, 2]-1)) + eulerphi(f) + bigomega(f)^5; } \\ Amiram Eldar, Feb 19 2026

Crossrefs

Cf. A000203, A001615, A000010, A001222, A390049, A393229, A393230, A393425.

Sequence in context: A233790 A378097 A359127 * A223457 A338541 A190377

Adjacent sequences: A391445 A391446 A391447 * A391449 A391450 A391451

Keyword

nonn,hard,more

Author

S. I. Dimitrov, Feb 18 2026

Extensions

a(17)-a(18) from Michael S. Branicky, Feb 18 2026

a(19)-a(20) from Amiram Eldar, Feb 19 2026

Status

approved