%I #8 Apr 05 2015 14:14:56

%S 3,35,3537,35373539,3537353935373551,35373539353735513537353935373569,

%T 3537353935373551353735393537356935373539353735513537353935373613

%N a(1) = 3, a(n+1) is the concatenation of a(n) and the next prime after a(n).

%t NextPrim[n_] := Block[{k = n + 1}, While[ !PrimeQ[k], k++ ]; k]; f[n_] := ToExpression[ ToString[n] <> ToString[ NextPrim[n]]]; NestList[f, 3, 7]

%t NestList[FromDigits[Join[IntegerDigits[#],IntegerDigits[NextPrime[ #]]]]&,3,6] (* _Harvey P. Dale_, Apr 05 2015 *)

%Y Cf. A067823, A068003, A068004.

%K easy,nonn,base

%O 1,1

%A _Robert G. Wilson v_, Feb 10 2002