A353806 a(n) = A353802(n) / gcd(A051027(n), A353802(n)), where A051027(n) = sigma(sigma(n)), and A353802(n) = Product_{p^e||n} sigma(sigma(p^e)).

1, 1, 1, 1, 1, 1, 1, 1, 1, 16, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 5, 16, 1, 1, 1, 1, 1, 1, 1, 112, 1, 1, 49, 13, 45, 1, 1, 1, 7, 16, 1, 5, 1, 1, 1, 16, 1, 1, 1, 1, 7, 64, 1, 1, 112, 1, 49, 16, 1, 7, 1, 1, 1, 1, 9, 784, 1, 1, 5, 720, 1, 1, 1, 1, 1, 1, 5, 7, 1, 1, 1, 16, 1, 5, 117, 1, 7, 16, 1, 16, 45, 1, 147, 16, 7

Offset

1,10

Comments

Numerator of fraction A353802(n) / A051027(n).

Links

Antti Karttunen, Table of n, a(n) for n = 1..20000

Index entries for sequences related to sigma(n)

Formula

a(n) = A353802(n) / A353804(n) = A353802(n) / gcd(A051027(n), A353802(n)).

Prog

(PARI)
A051027(n) = sigma(sigma(n));
A353806(n) = { my(f = factor(n), u=prod(k=1, #f~, A051027(f[k, 1]^f[k, 2]))); (u / gcd(A051027(n), u)); };

Crossrefs

Cf. A000203, A051027, A353802, A353803, A353804, A353805 (denominators).

Cf. A336547 (positions of 1's), A336548 (positions of terms > 1), see also A353807.

Cf. also A353755, A353756.

Sequence in context: A050467 A008835 A040259 * A040260 A325938 A361132

Adjacent sequences: A353803 A353804 A353805 * A353807 A353808 A353809

Keyword

nonn,frac

Author

Antti Karttunen, May 08 2022

Status

approved