A080695 Concatenation of the prime power factors (with maximal exponent) of n; a(1) = 1 by convention.

1, 2, 3, 4, 5, 23, 7, 8, 9, 25, 11, 43, 13, 27, 35, 16, 17, 29, 19, 45, 37, 211, 23, 83, 25, 213, 27, 47, 29, 235, 31, 32, 311, 217, 57, 49, 37, 219, 313, 85, 41, 237, 43, 411, 95, 223, 47, 163, 49, 225, 317, 413, 53, 227, 511, 87, 319, 229, 59, 435, 61, 231, 97, 64

Offset

1,2

Comments

a(n) = n iff n is 1 or a prime power; otherwise, a(n) > n. - Ivan Neretin, May 31 2016

Links

Ivan Neretin, Table of n, a(n) for n = 1..10000

Example

a(67500) = a(2^2*3^3*5^4) = a(4*27*625) = 427625.

Mathematica

Table[FromDigits@Flatten@IntegerDigits[#[[1]]^#[[2]] & /@ FactorInteger[n]], {n, 64}] (* Ivan Neretin, May 31 2016 *)

Crossrefs

Cf. A037276, A067599, A080670, A230305.

Sequence in context: A248901 A280849 A037400 * A239448 A248713 A242799

Adjacent sequences: A080692 A080693 A080694 * A080696 A080697 A080698

Keyword

nonn,base

Author

Vladeta Jovovic, Mar 03 2003

Extensions

Edited by Charles R Greathouse IV, Apr 29 2010

Status

approved