OFFSET
1,2
EXAMPLE
120 = 2^3 * 3 * 5 has a unitary divisor 8 for which sigma(8) = 15 = 120/8, thus 120 is included in the sequence.
672 = 2^5 * 3 * 7 has a unitary divisor 21 for which sigma(21) = 32 = 120/21, thus 672 is included in the sequence.
MATHEMATICA
q[n_] := DivisorSum[n, 1 &, CoprimeQ[#, n/#] && #*DivisorSigma[1, #] == n &] > 0; Select[Range[16256], q] (* Amiram Eldar, Sep 27 2021 *)
PROG
(PARI) isA348034(n) = { fordiv(n, d, if(1==gcd(d, n/d)&&n==d*sigma(d), return(1))); (0); };
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Sep 26 2021
STATUS
approved