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Primes with consecutive digits that differ exactly by 6.
6

%I #16 Aug 13 2024 15:41:57

%S 2,3,5,7,17,71,1717171717171717171717171717171,

%T 1717171717171717171717171717171717171

%N Primes with consecutive digits that differ exactly by 6.

%C From _Andrew Howroyd_, Aug 13 2024: (Start)

%C Terms with more than 1 digit have digits alternating between 1 and 7.

%C No more terms < 10^3000. (End)

%o (PARI) upto(limit)={my(L=List([t|t<-[2,3,5],t<=limit]),m=1); while(m<limit, foreach([m*17\10, m*71\10, m*17, m*71], t, if(isprime(t)&&t<=limit, listput(L,t))); m=m*100+1); Vec(L)}

%o upto(10^100) \\ _Andrew Howroyd_, Aug 13 2024

%Y Primes in A048408.

%Y Cf. A048398, A048399, A048400, A048401, A048402, A048404, A048405.

%K nonn,base

%O 1,1

%A _Patrick De Geest_, Apr 15 1999

%E Offset changed by _Andrew Howroyd_, Aug 13 2024