OFFSET
1,2
COMMENTS
Prime(n) is all zeros followed by prime(n). This is all ones followed by prime(n). Conjecture: No term is zero except a(1) = a(3) = 0.
EXAMPLE
a(7) = 1117, as 117 is composite prime(8) = 17.
MATHEMATICA
spf[n_]:=Module[{x=IntegerLength[n]+1, idn=IntegerDigits[n]}, While[ !PrimeQ[ FromDigits[ PadLeft[ idn, x, 1]]], x++]; FromDigits[ PadLeft[ idn, x, 1]]]; Join[{0, 13, 0}, spf/@Prime[Range[4, 30]]] (* Harvey P. Dale, May 22 2014 *)
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Amarnath Murthy, Nov 17 2005
EXTENSIONS
More terms from Joshua Zucker, May 06 2006
STATUS
approved