OFFSET
1,1
LINKS
Jens Kruse Andersen, Table of n, a(n) for n = 1..10000
EXAMPLE
a(1)=422 since 4=2*2 and 4 is the first composite integer.
MATHEMATICA
f[n_]:=FactorInteger[n]; con[A_]:=(v1={}; l=Length[A]; Do[v1=Join[v1, IntegerDigits[A[[k]]]], {k, l}]; FromDigits[v1]); alfa[n_]:=(b=f[n]; j=Length[b]; c=Table[Table[b[[k]][[1]], {b[[k]][[2]]}], {k, j}]; w={}; Do[w=Join[w, c[[k]]], {k, j}]; con[w]); na[n_]:=con[{n, alfa[n]}]; v=Select[Range[2, 1000], !PrimeQ[#]&]; Table[na[v[[k]]], {k, 32}]
ncpf[n_]:=FromDigits[Join[IntegerDigits[n], Flatten[IntegerDigits/@Table[ #[[1]], #[[2]]]&/@FactorInteger[n]]]]; ncpf/@Select[Range[ 100], CompositeQ] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jul 03 2019 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Jahangeer Kholdi, Sep 15 2014
STATUS
approved