OFFSET
1,1
LINKS
Jens Kruse Andersen, Table of n, a(n) for n = 1..10000
EXAMPLE
a(8)=158 since 15 is the 8th composite integer.
MATHEMATICA
w=Select[Range[2, 57], !PrimeQ[#]&]; Table[FromDigits[Flatten[{IntegerDigits[w[[n]]], IntegerDigits[n]}]], {n, 1, 40}]
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Jahangeer Kholdi, Sep 15 2014
STATUS
approved