A319067 a(n) is the least k such that n divides A047994(k) where A047994 is the unitary totient function.

1, 3, 4, 5, 11, 7, 8, 9, 19, 11, 23, 13, 27, 24, 16, 17, 103, 19, 191, 33, 43, 23, 47, 25, 101, 27, 76, 29, 59, 31, 32, 45, 67, 103, 71, 37, 149, 191, 79, 41, 83, 43, 173, 69, 112, 47, 283, 49, 197, 101, 103, 53, 107, 76, 253, 72, 229, 59, 709, 61, 367, 96, 64, 85, 131

Offset

1,2

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

József Sándor, The Unitary Totient Minimum and Maximum Functions, Studia Universitatis Babes-Bolyai Mathematica, Volume L, Number 2, June 2005.

Formula

a(p-1) = p for p prime. See Sándor link Theorem 2 p. 95.

Prog

(PARI) a047994(n) = prod(i=1, #n=factor(n)~, n[1, i]^n[2, i]-1);
a(n) = my(k=1); while(a047994(k) % n, k++); k;

Crossrefs

Cf. A047994 (unitary totient).

Cf. A005179 (analog for number of divisors), A061026 (analog for Euler totient), A070982 (analog for sum of divisors).

Sequence in context: A225906 A332790 A329524 * A224503 A349005 A128920

Adjacent sequences: A319064 A319065 A319066 * A319068 A319069 A319070

Keyword

nonn

Author

Michel Marcus, Sep 09 2018

Status

approved