A351096 Semiprimes that are the arithmetic derivative (A003415) of some number.

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

Author

Antti Karttunen, Feb 03 2022

Keywords

• nonn

Crossrefs

Complement of A351095 in A001358. Subsequence of A239433.

Cf. A003415, A189441.

Programs

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));