A349866 Fixed points of A318996.

4, 45, 6048, 14421, 26409026, 29270772, 30685402

Offset: 1

Author

Michel Marcus, Dec 03 2021

Keywords

• nonn
• more

Comments

Integers m such that Sum_{d|m} (sigma(m) mod d) = m.

Examples

			The sum of divisors of 4 is 7 with divisors 1, 2, 4; And (7 mod 1) + (7 mod 2) + (7 mod 4) = 0 + 1 + 3 = 4.
		

Links

• Carlos Rivera, Puzzle 1065. A larger integer than 45 such that ..., The Prime Puzzles and Problems Connection.

Crossrefs

Cf. A000203, A318996.

Programs

PARI

isok(m) = my(sn = sigma(m)); sumdiv(m, d, sn % d) == m;

Python

from itertools import count, islice
from sympy import divisor_sigma, divisors
def A349866gen(): # generator of terms
    return filter(lambda m: sum(divisor_sigma(m) % d for d in divisors(m,generator=True)) == m, count(1))
A349866_list = list(islice(A349866gen(),4)) # Chai Wah Wu, Dec 03 2021