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A351096
Semiprimes that are the arithmetic derivative (A003415) of some number.
1
4, 6, 9, 10, 14, 15, 21, 22, 25, 26, 33, 34, 38, 39, 46, 49, 51, 55, 58, 62, 69, 74, 77, 82, 85, 86, 87, 91, 94, 95, 106, 111, 115, 118, 119, 121, 122, 123, 129, 133, 134, 141, 142, 143, 146, 155, 158, 159, 161, 166, 169, 178, 183, 185, 187, 194, 201, 202, 203, 206, 213, 214, 215, 218, 221, 226, 235, 247, 249, 253
OFFSET
1,1
PROG
(PARI)
A002620(n) = ((n^2)>>2);
A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
isA351096(n) = if(2!=bigomega(n), 0, for(k=1, A002620(n), if(A003415(k)==n, return(1))); (0));
CROSSREFS
Complement of A351095 in A001358. Subsequence of A239433.
Sequence in context: A226526 A103607 A264815 * A108574 A157931 A338904
KEYWORD
nonn
AUTHOR
Antti Karttunen, Feb 03 2022
STATUS
approved