A193551 Smallest number with n as multiplicative projection.

1, 2, 3, 4, 5, 6, 7, 16, 27, 10, 11, 12, 13, 14, 15, 256, 17, 24, 19, 20, 21, 22, 23, 36, 3125, 26, 19683, 28, 29, 30, 31, 65536, 33, 34, 35, 72, 37, 38, 39, 80, 41, 42, 43, 44, 135, 46, 47, 144, 823543, 160, 51, 52, 53, 216, 55, 112, 57, 58, 59, 60, 61, 62

Offset

1,2

Comments

A000026(a(n)) = n and A000026(m) <> n for m < a(n);

a(p^k) = p^(p^(k-1)), p prime, k > 0; the sequence is not multiplicative, but for coprime odd numbers u, v: a(u*v) = a(u) * a(v);

A078779 gives fixed points: a(A078779(n)) = A078779(n).

Links

Table of n, a(n) for n=1..62.

Prog

(Haskell)
import Data.List (elemIndex, findIndices)
import Data.Maybe (fromJust)
a193551 n = (fromJust $ elemIndex n a000026_list) + 1

Crossrefs

Sequence in context: A132028 A332535 A285724 * A277439 A069188 A085158

Adjacent sequences: A193548 A193549 A193550 * A193552 A193553 A193554

Keyword

nonn

Author

Reinhard Zumkeller, Aug 27 2011

Status

approved