A392385 Numbers k such that sigma(k) = psi(k) + tau(k) + omega(k)^7.

27240, 29832, 31640, 34040, 35224, 61290, 67122, 84915, 170250, 178802, 197750, 212750, 235875, 387590, 431494, 902418, 2544934, 2726715, 4501790, 11650190, 12055414, 12916515, 95231202, 101002790, 350912490

Offset

1,1

Links

Table of n, a(n) for n=1..25.

Example

27240 is a term since sigma(27240) = 82080 = 65664 + 32 + 4^7 = psi(27240) + tau(27240) + omega(27240)^7.

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)^7; } \\ Amiram Eldar, Jan 09 2026

Crossrefs

Cf. A000203 (sigma), A001615 (psi), A000005 (tau), A001221 (omega), A386637, A392263, A391447, A392384.

Sequence in context: A216943 A250852 A157820 * A251777 A032746 A099230

Adjacent sequences: A392382 A392383 A392384 * A392386 A392387 A392388

Keyword

nonn,hard,more

Author

S. I. Dimitrov, Jan 09 2026

Extensions

a(23)-a(25) from Amiram Eldar, Jan 09 2026

Status

approved