A135076 - OEIS

%I #12 Oct 13 2013 06:08:15

%S 2,7,5,11,13,7,19,19,29,31,41,37,29,43,41,37,47,61,59,67,71,61,73,79,

%T 89,109,103,89,109,107,107,113,139,151,127,137,107,113,167,173,167,

%U 181,191,173,193,223,233,211,199,229,251,239,281,251,277,281,239,241,239,269

%N Primes appearing in A001370.

%H Zak Seidov, <a href="/A135076/b135076.txt">Table of n, a(n) for n = 1..1000.</a>

%F a(n)=A007953(2^A076203(n)).

%e a(1)=2 because with s=A076203(1)=1, 2^s=2 and sod(2)=2; sod(x)=sum of digits of x;

%e a(2)=7 because with s=A076203(2)=4, 2^s=16 and sod(16)=7.

%e a(7)=9 because with s=A076203(7)=12, 2^s=4096 and sod(4096)=19.

%e a(8)=9 because with s=A076203(8)=18, 2^s=262144 and sod(262144)=19.

%o (PARI) lista(nn) = {for (n=1, nn, sd = sumdigits(2^n); if (isprime(sd), print1(sd, ", ")););} \\ _Michel Marcus_, Oct 13 2013

%Y Cf. A001370, A076203.

%K base,nonn

%O 1,1

%A _Zak Seidov_, Nov 18 2007

%E Name corrected by _Michel Marcus_, Oct 13 2013