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A303480
Numbers k such that the average of squarefree kernels of all positive integers <= k is an integer.
3
1, 3, 4, 17, 53, 433, 456, 901, 1052, 4011, 14504, 15111, 156408, 245423, 328408, 911340, 2263141, 13736475, 20092485, 37903271, 60003559, 78733423, 84206981, 234095587, 319691535, 986119609, 1488787296, 6139123252, 8663152552, 11909530004, 19226378456, 65827587400
OFFSET
1,2
COMMENTS
Numbers k such that k | A073355(k).
EXAMPLE
3 is a term because the first 3 terms of A007947 are 1, 2 and 3 whose sum is divisible by 3.
PROG
(PARI) isok(k) = sum(i=1, k, factorback(factor(i)[, 1])) % k == 0; \\ Michel Marcus, Apr 25 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Apr 24 2018
EXTENSIONS
a(13)-a(17) from Alois P. Heinz, Apr 24 2018
a(18)-a(26) from Daniel Suteu, Apr 24 2018
a(27)-a(32) from Giovanni Resta, Apr 26 2018
STATUS
approved