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%I #26 Sep 08 2022 08:45:12
%S 3,35,357,35711,3571113,357111317,35711131719,3571113171923,
%T 357111317192329,35711131719232931,3571113171923293137,
%U 357111317192329313741,35711131719232931374143,3571113171923293137414347,357111317192329313741434753,35711131719232931374143475359
%N Concatenate the first n odd primes.
%C Except for a(1) = 3, these numbers are not prime for n < 10000. See A089948.
%H Robert Israel, <a href="/A089933/b089933.txt">Table of n, a(n) for n = 1..298</a>
%p a[1]:= 3;
%p for n from 2 to 100 do
%p p:= ithprime(n+1);
%p a[n]:= 10^(1+ilog10(p))*a[n-1]+p
%p od:
%p seq(a[i],i=1..100); # _Robert Israel_, Aug 25 2016
%t Table[FromDigits[Flatten[IntegerDigits[Prime[Range[n] + 1]]]],{n, 20}] (* _Vincenzo Librandi_, Nov 30 2015 *)
%o (PARI) concatprime(n) = { y=""; forprime(x=3,n, y=concat(Str(y),Str(x)); z=eval(y); print1(z",") ) }
%o (Magma) [Seqint(Reverse(&cat[Reverse(Intseq(NthPrime(k+1))): k in [1..n]])): n in [1..17]]; // _Vincenzo Librandi_, Nov 30 2015
%Y Cf. A019518, A086043, A089948.
%K nonn,base
%O 1,1
%A _Cino Hilliard_, Jan 11 2004
%E Offset changed by _Robert Israel_, Aug 25 2016
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