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 A072623 #15 Aug 03 2017 04:26:21
%S A072623 4,5,6,11,19,25,34,36,75,82,87,90,94,237,604,609,614,1583,1592,10466,
%T A072623 10467,10498,10504,10505,70501,70511,180227,180294,180358,180443,
%U A072623 180447,466078,8103422,21058343,21058649,143052872,143052877,143053068
%N A072623 Numbers n such that A065863(n) = 1, i.e., prime(n) mod (n - Pi(n)) = 1.
%C A072623 A004648, A065134 and A065863 behave similarly; they grow relatively slowly and drop suddenly at unexpected values of n. Parity of A004648 behaves most regularly.
%C A072623 Each cluster of entries exceeds the previous cluster by a power of e.
%e A072623 For the cluster started at n = 10466 the remainders of A065863(n) are as follows: {9089, 9092, 9117, 9127, 9148, 9159, 1, 1, 9180, 9183, 9182, 9179, 9172, 9169, 9168, 9177, 9176, 9178, 9183, 9192, 43}. It behaves like A004648 or A065134.
%t A072623 Do[ If[ Mod[ Prime[n], n-PrimePi[n]] == 1, Print[n]], {n, 1, 150000000}]
%t A072623 (* Second program: *)
%t A072623 Position[Table[Mod[Prime[n], n - PrimePi[n]], {n, 10^6}], 1] // Flatten (* _Michael De Vlieger_, Jul 30 2017 *)
%Y A072623 Cf. A065860-A065863, A065133-A065135, A072608-A072610, A004648, A057809.
%K A072623 nonn
%O A072623 1,1
%A A072623 _Labos Elemer_, Jun 26 2002
%E A072623 Edited by _Robert G. Wilson v_, Jun 27 2002