%I #12 Jul 29 2021 22:30:55
%S 2,3,15,22,98,460,5408,21170,243568,3587402,25881424,25888784,
%T 33305870,61202192,115333190,135135182,167241932,788355824,788360176,
%U 1653570248
%N Numbers k such that |s(k) - k| = number of primes <= k, where s(k) is sigma(k) - k.
%C a(21) > 10^11. - _Donovan Johnson,_ Aug 15 2011
%p with(numtheory):np:=0: for n from 1 to 300000 do if isprime(n) then np:=np+1 fi: if(abs(sigma(n)-2*n)=np) then printf("%d, ",n) fi od: (C. Ronaldo)
%o (PARI) np=0;for(n=1,10000000,if(isprime(n),np=np+1);if(abs(sigma(n)-2*n)==np,print1(n,","))) (Ronaldo)
%K nonn
%O 1,1
%A _Naohiro Nomoto_
%E More terms from C. Ronaldo (aga_new_ac(AT)hotmail.com), Dec 30 2004
%E a(11)-a(20) from _Donovan Johnson_, Aug 15 2011