OFFSET
1,1
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..200
MATHEMATICA
cc[x_]:=FromDigits[Flatten[IntegerDigits/@x]]; Module[{nn= 100, cmps, tr, len}, cmps = Select[Range[nn], CompositeQ]; len=Length[cmps]; tr = Floor[ (Sqrt[1+8 len]-1)/2]; cc/@TakeList[cmps, Range[tr]]] (* Harvey P. Dale, Sep 26 2021 *)
CROSSREFS
KEYWORD
base,easy,nonn
AUTHOR
Omar E. Pol, Nov 26 2007
STATUS
approved