%I #19 Feb 16 2025 08:33:42
%S 1,555,1508,1781,4224,7037
%N Numbers k such that A011544(k-1) is a prime.
%C For k <= 16000, there are six primes in sequence A011544.
%C Round(e*10^112279) = floor(e*10^112279), and floor(e*10^112279) = A011544(112279) (=A007512(7)) is a prime. Thus 112280 = A064118(7) is also a term.
%H Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/e-Prime.html">e-Prime</a>
%t Do[If[PrimeQ[Round[E*10^(n-1)]],Print[n],{n,16000}]
%Y Cf. A007512, A011543, A011544, A064118.
%K nonn,base,more,changed
%O 1,2
%A _XU Pingya_, Mar 01 2017