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A375488
Numbers k such that k^(sigma(k) - k) == k (mod sigma(k)), where sigma = A000203.
1
1, 2, 3, 5, 7, 9, 10, 11, 13, 15, 17, 18, 19, 23, 27, 29, 31, 32, 33, 35, 36, 37, 41, 43, 47, 53, 55, 59, 61, 65, 67, 71, 73, 79, 83, 87, 89, 91, 95, 97, 98, 99, 101, 103, 107, 109, 112, 113, 119, 127, 131, 135, 136, 137, 139, 143, 145, 149, 151, 157, 161, 163, 167, 173, 179, 181, 191, 193, 195, 197, 199
OFFSET
1,2
EXAMPLE
9 is in this sequence because 9^(sigma(9) - 9) = 9^(13 - 9) = 9^4 = 6561 modulo 13 is equal to 9.
PROG
(Magma) [1] cat [k: k in [2..200] | k^(SumOfDivisors(k)-k) mod SumOfDivisors(k) eq k];
(PARI) isok(k) = Mod(k, sigma(k))^(sigma(k) - k) == k; \\ Michel Marcus, Aug 18 2024
CROSSREFS
Supersequence of A000040.
Sequence in context: A195921 A175089 A047489 * A196499 A035061 A302403
KEYWORD
nonn
AUTHOR
STATUS
approved