A389972 Numbers k such that sigma(k) = psi(k) + phi(k) + omega(k)^7.

32512, 49296, 196096, 198100, 462612, 750324, 892884, 1080660, 1454484, 2270964, 3534570, 3609620, 3630500, 4055124, 5778804, 6413844, 7115412, 7590612, 8219604, 8476212, 9275412, 10185204, 10435764, 10614612, 11038734, 11407410, 11524404, 11688564, 11727444, 11802612, 12038484, 12323604, 12450612

Offset

1,1

Links

Table of n, a(n) for n=1..33.

Example

32512 is a term since sigma(32512) = 65408 = 49152 + 16128 + 2^7 = psi(32512) + phi(32512) + omega(32512)^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)) + eulerphi(f) + omega(f)^7; } \\ Amiram Eldar, Dec 27 2025

Crossrefs

Cf. A000203 (sigma), A001615 (psi), A000010 (phi), A001221 (omega), A390049, A391312, A391749, A391763, A391908, A391949.

Sequence in context: A233680 A243857 A028240 * A393848 A251000 A134698

Adjacent sequences: A389969 A389970 A389971 * A389973 A389974 A389975

Keyword

nonn

Author

S. I. Dimitrov, Dec 27 2025

Status

approved