A090690 - OEIS

%I #3 Oct 01 2013 17:57:57

%S 13,29,37,53,61,73,97,101,109,127,137,149,157,173,181,193,197,229,257,

%T 269,277,293,317,337,349,373,389,397,421,457,461,487,509,541,557,569,

%U 577,613,617,641,653,661,673,677,701,709,733,757,773,797,809,811,821

%N Repeated primes in first occurrence in the progression kx^2+1.

%C The program lists the repeated occurrences. All but one repeated occurrence were removed manually.

%o (PARI) mx2pmp(n,m) = { v=vector(n+1); c=0; for(a=1,n, for(x=1,n, y = a*x^2+1; if(isprime(y),c++;v[c]=y;break); ); ); v1=vecsort(v); for(j=1,n,if(v1[j]<>0 && v1[j]==v1[j+1],print1(v1[j]","))) }

%K easy,nonn

%O 1,1

%A _Cino Hilliard_, Dec 18 2003