%I #6 Mar 24 2023 17:50:07
%S 5,23,599,
%T 7899999999999999999999999999999999999999999999999899999999999999999
%N a(1) = 5; a(n+1) is the smallest prime p > a(n) such that digsum(p) = a(n).
%e a(3) = 599 because 599 is the smallest prime > a(2) whose sum of digits is 5 + 9 + 9 = 23 = a(2).
%Y Cf. A007953, A046704, A062802.
%K nonn,base
%O 1,1
%A _Ya-Ping Lu_, Mar 10 2023