A168145 - OEIS

%I #9 Apr 06 2018 17:41:17

%S 1,5,6,12,18,24,36,42,48,60,84

%N Numbers n such that to abs(phi(n) - pi(n)) = 1.

%C No more terms between 84 and 120000. - _R. J. Mathar_, Jun 04 2010

%F Solutions to A000010(x)=A000720(x)+k where k=+-1; finite for any fixed value of k.

%e 15 primes below 48=(2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47); 16 terms in RRS(48)=(1, 5, 7, 11, 13, 17, 19, 23, 25, 29, 31, 35, 37, 41, 43, 47), so 48 is here.

%Y Cf. A000010, A000720, A037121, A037228, A073456.

%K nonn

%O 1,2

%A _Juri-Stepan Gerasimov_, Nov 19 2009

%E Corrected (42 inserted) by _R. J. Mathar_, Jun 04 2010