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 A245823 #19 Apr 01 2025 17:48:44 %S A245823 1,2,3,4,5,7,11,17,24,31,59,89,127,184,277,461,669,709,1097,1787,1995, %T A245823 3259,4999,5381,8807,15299,17351,30133,48593,52711,60810,91081,167449, %U A245823 192263 %N A245823 Fixed points of A245821 and A245822. %C A245823 If n is a member, then the n-th prime, p_n (= A000040(n)) is also a member. If p_n is a member, then its index n is also a member. Thus the sequence is completely determined by its nonprime terms: 1, 4, 24, 184, 669, 1995, 60810, ..., and is obtained as a union of prime recurrences that start with those values: A007097 U A057450 U ..., etc. %o A245823 (PARI) %o A245823 default(primelimit, 2^30);for(n=1, 2^18, if(A245821(n) == n, print1(n, ", "))); \\ Other code as in A245821. %o A245823 (Scheme) %o A245823 ;; With _Antti Karttunen_'s IntSeq-library. %o A245823 (define A245823 (FIXED-POINTS 1 1 A245821)) %Y A245823 A007097 and A057450 are subsequences. %Y A245823 Cf. A000040, A245821, A245822. %K A245823 nonn %O A245823 1,2 %A A245823 _Antti Karttunen_, Aug 02 2014