Sequences

Numbers k such that phi(k) | sigma_3(k).

Numbers n such that phi(n) | sigma_4(n).

Numbers k such that phi(k) divides sigma_5(k).

Numbers n such that phi(n) | sigma_6(n).

Numbers n such that phi(n) | sigma_7(n).

Numbers k such that phi(k) | sigma_8(k).

Numbers k such that phi(k) | sigma_9(k).

Numbers k such that phi(k) | sigma_10(k).

Numbers k such that phi(k) | sigma_11(k).

Numbers k such that phi(k) divides sigma_12(k).

Numbers k such that phi(k) | sigma_13(k).

Inverse of 1763rd cyclotomic polynomial.

Numbers k such that phi(k) | sigma_14(k).

Numbers k such that phi(k) | sigma_15(k).

Numbers n such that (phi(n) + 1) | sigma(n + 1), where phi is Euler's totient function A000010.

Inverse of 1767th cyclotomic polynomial.

Inverse of 1768th cyclotomic polynomial.

Inverse of 1769th cyclotomic polynomial.

Inverse of 1770th cyclotomic polynomial.

Inverse of 1771st cyclotomic polynomial.

Numbers k such that phi(k) + 2 | sigma(k + 2).

Numbers k such that phi(k) + 3 | sigma(k + 3).

Numbers k such that phi(k) + 4 | sigma(k + 4).

Phi(n) + 5 | sigma(n + 5).

Phi(n) + 6 | sigma(n + 6).

Numbers k such that phi(k) + 7 | sigma(k + 7).

Numbers n such that phi(n) + 8 | sigma(n + 8), where phi = A000010 and sigma = A000203.

Numbers k such that phi(k) + 9 | sigma(k + 9).

Numbers k such that phi(k) + 10 | sigma(k + 10).

Inverse of 1781st cyclotomic polynomial.

a(n) is the smallest integer k such that phi(k) + n | sigma(k + n).

Numbers k such that phi(k) + 3 | sigma(k).

Numbers n such that phi(n) + 4 divides sigma(n).

Inverse of 1785th cyclotomic polynomial.

Inverse of 1786th cyclotomic polynomial.

Numbers k such that phi(k) + 5 | sigma(k).

Numbers n such that phi(n) + 6 | sigma(n).

Numbers k such that phi(k) + 7 | sigma(k).

phi(n) + 8 | sigma(n).

Numbers k such that phi(k) + 9 | sigma(k).

Numbers k such that phi(k) + 10 | sigma(k).

Inverse of 1793rd cyclotomic polynomial.

Inverse of 1794th cyclotomic polynomial.

Numbers k such that phi(k) + 11 | sigma(k).

Numbers k such that phi(k) + 12 | sigma(k).

Numbers k not congruent to 0 (mod 3) such that phi(k) + 4 | sigma(k).

Inverse of 1798th cyclotomic polynomial.

k is the first integer such that phi(k) + n | sigma(k).

Odd numbers k such that phi(k) | sigma_3(k).

k is the first integer such that phi(k+n) | sigma(k)+n.