A379125 Sum of divisors of those odd squares k for which A379113(k) > 1, i.e., k that have a proper unitary divisor d > 1 such that A048720(A065621(sigma(d)),sigma(k/d)) is equal to sigma(k).

403, 4123, 4953, 18291, 46101, 73749, 133939, 400179, 291441, 542469, 618673, 1153633, 1119859, 1098867, 1077699, 1599249, 2309619, 6848721, 20421219, 20131059, 17598529, 17022999, 44205381, 59669253, 80520921, 68946969, 88131729, 83998281, 88119813, 97595019, 102760497, 137273157, 147291249, 211492119, 574669953

Offset: 1

Author

Antti Karttunen, Dec 18 2024

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..2025
• Index entries for sequences defined by congruent products between domains N and GF(2)[X].
• Index entries for sequences related to polynomials in ring GF(2)[X].
• Index entries for sequences related to sigma(n).

Crossrefs

Cf. A000203, A048720, A065621, A277320, A379113, A379121, A379123, A379124.

Programs

PARI

forstep(n=1,oo,2,if(A379113(n^2)>1, k++; print1(sigma(n^2), ", ")));

Formula

a(n) = A000203(A379121(n)).

a(n) = A277320(sigma(A379123(n)), sigma(A379124(n))).

a(n) = sigma(A379123(n)) * sigma(A379124(n)).