1,2

Numbers k such that A003961(k) is in A003601. Numbers which become (or stay as) arithmetic numbers when all primes in their prime factorization are replaced by the next larger primes.

Numbers k for which A003973(k) is equal to A000005(k)*A336838(k).

Antti Karttunen, Table of n, a(n) for n = 1..10000

Wikipedia, Arithmetic number

Index entries for sequences computed from indices in prime factorization

(PARI)

A003961(n) = { my(f = factor(n)); for(i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); };

isA336918(n) = !(sigma(A003961(n))%numdiv(n));

Cf. A000005, A003601, A003961, A003973, A336838, A336930.

Positions of ones in A336839.

Cf. A336919 (complement).

Sequence in context: A158276 A028793 A028753 * A028745 A028777 A028962

Adjacent sequences: A336915 A336916 A336917 * A336919 A336920 A336921

nonn

Antti Karttunen, Aug 12 2020

approved