A275463 Least k such that n divides d(k*n) (d = A000005).

1, 1, 3, 2, 16, 2, 64, 3, 4, 8, 1024, 5, 4096, 32, 48, 24, 65536, 10, 262144, 12, 192, 512, 4194304, 15, 400, 2048, 900, 48, 268435456, 24, 1073741824, 60, 3072, 32768, 5184, 35, 68719476736, 131072, 12288, 42, 1099511627776, 96, 4398046511104

Offset

1,3

Links

Table of n, a(n) for n=1..43.

Example

a(5) = 16 because 5 divides A000005(16*5) = 10.
a(40) = 42 because 40 divides A000005(42*40) = 40.

Prog

(PARI) a(n) = if(isprime(n) && n>3, 2^(n-1), {my(k=1); while(numdiv(k*n) % n != 0, k++); k; })

Crossrefs

Cf. A000005, A076931.

Sequence in context: A126323 A292123 A084886 * A338280 A304989 A055864

Adjacent sequences: A275460 A275461 A275462 * A275464 A275465 A275466

Keyword

nonn

Author

Altug Alkan, Jul 28 2016

Status

approved