This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A065139 #29 Oct 16 2019 06:08:38 %S A065139 1,2,7,9,23,57,149,368,921,5863,14531,36087,36255,36257,233084, %T A065139 1505984,1151321194,1151321361,7826138122,967823489175,967823489458, %U A065139 967823489477,967823489490,967823489491,2545928465925,123116092093107,123116092093185,123116092094024 %N A065139 Numbers n such that the sum of prime(n) and pi(n) is divisible by n. %H A065139 Giovanni Resta, <a href="/A065139/b065139.txt">Table of n, a(n) for n = 1..33</a> %F A065139 Solutions to pi(x) + prime(x) = A000720(x) + A000040(x) = 0 (mod x). %e A065139 p(233084) = 3242497, Pi(233084) = 20679; sum = 3263176 = 14*233084; order of quotient is log(n). %e A065139 (prime(1505984) + pi(1505984))/1505984 = (23981141 + 114603)/1505984 = 16. %t A065139 Do[ If[ IntegerQ[ (Prime[n] + PrimePi[n]) /n ], Print[n]], {n, 1, 5*10^7} ] %t A065139 Select[ Range[10^8], IntegerQ[(Prime[ # ] + PrimePi[ # ])/ # ] & ] %o A065139 (PARI) k=0;n=0;forprime(p=2,4e9,if(isprime(n++),k++);if((k+p)%n==0,print1(n", "))) \\ _Charles R Greathouse IV_, Aug 21 2011 %Y A065139 Cf. A000040, A000720, A006988. %K A065139 nonn %O A065139 1,2 %A A065139 _Labos Elemer_, Oct 16 2001 %E A065139 a(17)-a(19) from _Donovan Johnson_, Aug 21 2011 %E A065139 a(20)-a(28) from _Giovanni Resta_, Oct 15 2019