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 A085888 #11 Oct 05 2017 13:25:03 %S A085888 2,4,5,7,7,9,9,11,12,15,13,15,15,17,18,21,19,21,21,23,24,27,25,27,28, %T A085888 31,30,36,31,33,33,35,36,39,38,44,39,41,42,45,43,45,45,47,48,51,49,51, %U A085888 52,55,54,60,55,57,58,61,60,66,61,63,63,65,66,69,68,74,69,71,72,75,73,75 %N A085888 Let r and s be such that r + s = n; a(n) = minimum value of sigma(r) + sigma(s). %C A085888 a(p+1) = p+2 if p is a prime. %H A085888 Charles R Greathouse IV, <a href="/A085888/b085888.txt">Table of n, a(n) for n = 2..10000</a> %e A085888 a(8) = 9: the partitions are ( 1,7),(2,6),(3,5),(4,4) which give 9,15,10,14 as the sum of sigma functions of both the parts. %t A085888 Table[Min[Total[#]&/@(DivisorSigma[1,#]&/@({#,n-#}&/@Range[n/2]))],{n,2,80}] (* _Harvey P. Dale_, Oct 05 2017 *) %o A085888 (PARI) a(n)=my(best=sigma(n-1)+1); for(k=2, n\2, best=min(best, sigma(k)+sigma(n-k))); best \\ _Charles R Greathouse IV_, Apr 06 2012 %Y A085888 Cf. A085884. %K A085888 nonn %O A085888 2,1 %A A085888 _Amarnath Murthy_, Jul 08 2003 %E A085888 More terms from _David Wasserman_, Feb 10 2005