A084796 Replace n with concatenation of its prime factors in decreasing order.

1, 2, 3, 22, 5, 32, 7, 222, 33, 52, 11, 322, 13, 72, 53, 2222, 17, 332, 19, 522, 73, 112, 23, 3222, 55, 132, 333, 722, 29, 532, 31, 22222, 113, 172, 75, 3322, 37, 192, 133, 5222, 41, 732, 43, 1122, 533, 232, 47, 32222, 77, 552, 173, 1322, 53, 3332, 115, 7222, 193, 292

Offset: 1

Author

N. J. A. Sloane, Jul 19 2003

Keywords

• nonn
• base
• easy

Links

• Alois P. Heinz, Table of n, a(n) for n = 1..20000

Crossrefs

Cf. A032726, A085307, A084797.

Programs

Maple

with(numtheory):
a:= n-> parse(cat(`if`(n=1, 1,
    sort([seq(i[1]$i[2], i=ifactors(n)[2])], `>`)[]))):
seq(a(n), n=1..100);  # Alois P. Heinz, May 02 2016

Mathematica

Table[FromDigits[Flatten[Table[#[[1]],#[[2]]]&/@ Reverse[ FactorInteger[ n]]]],{n,60}] (* Harvey P. Dale, Aug 29 2016 *)

Extensions

More terms from Christopher N. Swanson (cswanson(AT)ashland.edu), Jul 22 2003