A391447 Numbers k such that sigma(k) = psi(k) + tau(k) + omega(k)^5.

80, 148, 333, 925, 1813, 2450, 4477, 6253, 10693, 13357, 19573, 31117, 35557, 62197, 68413, 81733, 103933, 128797, 137677, 166093, 186517, 197173, 230917, 254893, 293077, 348133, 377437, 392533, 423613, 439597, 472453, 596773, 634957, 694453, 714877, 821437, 843637, 912013, 983053, 1031893, 1185517

Offset

1,1

Links

Table of n, a(n) for n=1..41.

Example

80 is a term since sigma(80) = 186 = 144 + 10 + 2^5 = psi(80) + tau(80) + omega(80)^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)) + numdiv(f) + omega(f)^5; } \\ Amiram Eldar, Jan 09 2026

Crossrefs

Cf. A000203 (sigma), A001615 (psi), A000005 (tau), A001221 (omega), A386637, A392263.

Sequence in context: A202440 A248432 A107931 * A234134 A134769 A376909

Adjacent sequences: A391444 A391445 A391446 * A391448 A391449 A391450

Keyword

nonn

Author

S. I. Dimitrov, Jan 09 2026

Status

approved