A235376 - OEIS

%I #13 Apr 08 2020 00:22:32

%S 58,167,244,300,310,326,348,361,380,394,422,493,520,525,560,574,677,

%T 826,877,935,938,1010,1049,1116,1168,1201,1210,1212,1334,1346,1382,

%U 1411,1433,1585,1591,1640,1683,1750,1790,1796,1805,1848,1858,1891,1997,2032,2114

%N Positions of 9's in A235354.

%C If prime(a(n)) is written in base k, 2<=k<=9, and the k-representation is read in decimal, then it will be a prime only for k=9.

%o (PARI) isok(n) = {my(p = prime(n)); for (b = 2, 8, if (isprime(subst(Pol(digits(p, b)), x, 10)), return(0));); isprime(subst(Pol(digits(p, 9)), x, 10));} \\ _Michel Marcus_, Jan 18 2014

%Y Cf. A000040, A235354.

%K nonn,base

%O 1,1

%A _Vladimir Shevelev_ and _Peter J. C. Moses_, Jan 08 2014