login
Smallest number suffixed to concatenation of n times n gives a prime.
1

%I #8 Feb 11 2021 19:24:20

%S 2,1,3,1,9,7,29,1,3,7,39,1,23,1,97,1,91,37,59,9,93,19,97,61,293,61,3,

%T 1,57,7,43,61,7,53,31,127,353,67,841,187,9,3,179,429,127,97,3,319,11,

%U 51,39,191,33,3,41,7,39,47,73,81,401,57,441,571,957,997,1,19,291,173,9,417

%N Smallest number suffixed to concatenation of n times n gives a prime.

%e a(6) = 29 and 66666629 is prime.

%p a:= proc(n) local d, h, s;

%p s:= parse(cat(0, n$n));

%p for d from 0 do

%p for h to 10^d-1 do

%p if isprime(s+h) then return h fi

%p od:

%p s:= s*10;

%p od

%p end:

%p seq(a(n), n=0..75); # _Alois P. Heinz_, Feb 11 2021

%Y Cf. A088639.

%K base,nonn

%O 0,1

%A _Amarnath Murthy_, Oct 27 2003

%E More terms from _Ray Chandler_, Nov 01 2003

%E a(0)=2 prepended by _Alois P. Heinz_, Feb 11 2021