%I #7 Mar 04 2022 11:06:35

%S 1,2,2,3,5,5,7,11,11,13,13,17,19,19,23,23,29,31,31,37,37,41,43,43,47,

%T 47,53,53,59,61,61,67,67,71,71,73,79,79,83,83,89,97,97,101,101,103,

%U 103,107,109,109,113,113,127,127,131,131,137,139,139,149,149,151,151,157

%N a(1) = 1 and for n>1 a(n) = Max { q prime | q# < prime(n)# / q# } where prime(i) = A000040(i) and p(i)# = A002110(i), primorial.

%e prime(10) = 29: 2*3*5*7*11*13 < 17*19*23*29 and as 2*3*5*7*11*13*17 > 19*23*29 we have a(10) = 13.

%o (PARI) primo(n) = factorback(primes(n)); \\ A002110

%o a(n) = {if (n==1, 1, my(iq=2, P= primo(n)); while (sqr(primo(iq))<P, iq++); prime(iq-1););} \\ _Michel Marcus_, Mar 04 2022

%Y Cf. A000040, A002110.

%K nonn

%O 1,2

%A _Reinhard Zumkeller_, Oct 06 2001