A351443 Odd numbers k for which A003958(sigma(k)) = A003958(k), where A003958 is multiplicative with a(p^e) = (p-1)^e and sigma is the sum of divisors function.

1, 49, 40905, 106353, 140211, 275301, 302697, 499041, 597213, 1094913, 1284417, 1578933, 2004345, 2266137, 2560653, 3247857, 3444201, 3738717, 4425921, 5014953, 5123817, 5211297, 5407641, 5505813, 5996673, 6193017, 6870339, 7174737, 8156457, 8941833, 9432693, 9825381, 9923553

Offset

1,2

Comments

Odd numbers k for which A351442(k) = A003958(k), or equally, for which k = A351444(k) = A322582(k) + A351442(k).

The 13th term, 2004345, is one of the rare abundant numbers (A005101, A005231) in this sequence.

Links

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

Index entries for sequences where odd perfect numbers must occur, if they exist at all

Index entries for sequences related to sigma(n)

Prog

(PARI)
A003958(n) = { my(f = factor(n)); for(i=1, #f~, f[i, 1]--); factorback(f); };
A351442(n) = A003958(sigma(n));
isA351443(n) = ((n%2) && (A351442(n)==A003958(n)));

Crossrefs

Odd terms in A351446.

Cf. A000203, A003958, A005101, A005231, A322582, A351442, A351444, A351445.

These terms doubled form a subsequence of A351447.

Sequence in context: A173171 A100418 A369698 * A239169 A134725 A203499

Adjacent sequences: A351440 A351441 A351442 * A351444 A351445 A351446

Keyword

nonn

Author

Antti Karttunen, Feb 12 2022

Status

approved