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 A125841 #10 Aug 02 2025 12:13:07
%S A125841 144,288,1728,5184,7168,11760,21632,21952,73500,110592,113400,114244,
%T A125841 151263,153790,186624,205800,235298,250563,663552,708588,1404928,
%U A125841 2976750,3449628,4738500,5265000,7077888,9437184,11529602,11745162
%N A125841 Numbers k such that previous_prime(k)=k-sd and next_prime(k)=k+sd where sd is sum of the distinct prime factors of k.
%C A125841 14267656658790241528591830756844692582808594415616 is a 50-digit term of this sequence. 493009335 is the smallest number k such that previous_prime(k)=k-s and next_prime(k)=k+s where s is sum of the prime factors of k. What is the next number with the same property?
%e A125841 113400=2^3*3^4*5^2*7 is a term because previous_prime(113400)=113400-(2+3+5+7) and next_prime(113400)=113400+(2+3+5+7).
%t A125841 Do[If[c=Apply[Plus,PrimeFactorList[n]];n-c==PreviousPrime[n]&&n+c== NextPrime[n],Print[n]],{n,4,20000000}]
%Y A125841 Cf. A008472, A125840.
%K A125841 easy,nonn,base
%O A125841 1,1
%A A125841 _Farideh Firoozbakht_, Feb 04 2007, corrected Feb 08 2007