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 A244446 #10 Sep 03 2014 21:07:53 %S A244446 25,323,48,34,53,471,58,78,84,76,71,122,64,144,162,118,74,188,106,258, %T A244446 156,2512,68,254,94,107,132,2326,876,536,154,182,268,468,98,2061,106, %U A244446 408,264,286,258,1520900,423,618,276,648,579,518,204,708,196,370,164,1088,300,1518,412,3616,158,1226 %N A244446 a(n) is the smallest integer m such that m-n is composite and phi(m-n) + sigma(m+n) = 2*m. %C A244446 For each n, a(n)>n and like a(n)-n, a(n)+n is also composite. %C A244446 If both numbers p & p+2n are primes the x=p+n is a solution for the equation phi(x-n)+sigma(x+n)=2x. But for these many solutions x, both x-n & x+n are primes. %e A244446 a(1)=25 because 25-1 is composite, phi(25-1)+sigma(25+1)=2*25 and there is no such number less than 25. %t A244446 a[n_]:=(For[m=n+1, PrimeQ[m-n]||EulerPhi[m-n]+DivisorSigma[1,m+n]!=2m,m++];m);Table[a[n],{n,60}] %o A244446 (PARI) %o A244446 a(n)=m=n+4;while(isprime(m-n)||eulerphi(m-n)+sigma(m+n)!=2*m,m++);m %o A244446 vector(100,n,a(n)) \\ _Derek Orr_, Aug 30 2014 %Y A244446 Cf. A000010, A000203, A244447, A244448. %K A244446 nonn %O A244446 1,1 %A A244446 _Jahangeer Kholdi_ and _Farideh Firoozbakht_, Aug 30 2014