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 A260004 #31 Jan 11 2020 15:57:47 %S A260004 1,8,19,27,74,185,440,1015,2294,5109,10228,11252,24563,53234,114673, %T A260004 245744,524271,1114094,2359277,4980716,10485739,22020074,46137321, %U A260004 88080360,96468968,201326567,419430374,872415205,1811939300,15569256417 %N A260004 Values of f(2,x,y) in increasing order, for x>=0, y>0 where f is the Sudan function defined in A260002. %C A260004 This is a subsequence of A260003 since f(2,x,y)= f(1, f(2,x,y-1), f(2,x,y-1)+y). %C A260004 In this list we suppose that y>0. If we take y=0, all the natural numbers would be in the sequence. %C A260004 To evaluate the Sudan function see A260002-A260003. %e A260004 f(2,0,1) = f(1, f(2,0,0), f(2,0,0)+1) = f(1,0,1) = 2^1(0+2)-1-2 = 1; %e A260004 f(2,0,2) = f(1, [f(2,0,1)], [f(2,0,1)+1+1]) = f(1,1,3) = 2^3(1+2)-3-2 = 19; %Y A260004 Cf. A048493 (f(2,n,1)), A260002, A260003, A260005 (f(2,n,2)), A260006. %K A260004 nonn %O A260004 1,2 %A A260004 _Natan Arie Consigli_, Jul 23 2015