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 A115090 #16 Jan 06 2024 09:21:20 %S A115090 0,0,0,1,0,1,3,1,0,0,5,0,1,3,9,2,1,0,3,11,1,5,3,4,0,15,1,2,17,3,0,5,9, %T A115090 3,21,1,5,8,3,11,1,5,27,10,3,0,29,0,5,0,9,2,15,5,1,4,35,3,17,14,11,3, %U A115090 1,39,5,0,16,41,2,9,3,21,45,4,1,5,9,3,15,20,11,51,1,9,5,2,17,27,11,57,3,9,0 %N A115090 a(n) = A115074(n) - A117183(n). %C A115090 The union of A115090 is the complement of A007921: numbers that are not the difference of two primes. - _Robert G. Wilson v_, Mar 09 2006 %H A115090 Michael De Vlieger, <a href="/A115090/b115090.txt">Table of n, a(n) for n = 1..10000</a> %F A115090 a(n) = A046665(A013929(n)). - _Amiram Eldar_, Jan 06 2024 %e A115090 12, the 4th nonsquarefree positive integer, is 2^2 * 3. 3 is the largest prime dividing 12. 2 is the smallest prime dividing 12. So a(4) = 3 - 2 = 1. %t A115090 (Max@# - Min@#) & /@ (First /@ FactorInteger@# & /@ Select[ Range@243, !SquareFreeQ@# &]) (* _Robert G. Wilson v_, Mar 09 2006 *) %Y A115090 Cf. A007921, A013929, A046665, A115074, A115090, A117183. %K A115090 nonn %O A115090 1,7 %A A115090 _Leroy Quet_, Mar 01 2006 %E A115090 More terms from _Robert G. Wilson v_, Mar 09 2006