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 A122701 #10 Nov 09 2024 18:02:25
%S A122701 0,0,1,2,5,6,9,10,17,18,21,22,29,30,33,34,49,50,53,54,61,62,65,66,81,
%T A122701 82,85,86,93,94,97,98,129,130,133,134,141,142,145,146,161,162,165,166,
%U A122701 173,174,177,178,209,210,213,214,221,222,225,226,241,242,245,246,253,254
%N A122701 a(0)=0, a(n) = 2*a(floor(n/2)) + n - 1 for n > 0.
%C A122701 The recurrence defining this sequence arises in the study of the Merge Sort algorithm. By the master theorem, a(n) is in BigTheta(n*log_2(n)).
%p A122701 a[0]:=0: for n from 1 to 101 do a[n]:=2*a[floor(n/2)] + n-1; od: seq( a[n], n=0..101);
%t A122701 a[0]=0;a[n_]:=2*a[Floor[n/2]]+n-1;Table[a[n],{n,0,61}] (* _James C. McMahon_, Nov 09 2024 *)
%Y A122701 Cf. A080277.
%K A122701 nonn
%O A122701 0,4
%A A122701 Peter C. Heinig (algorithms(AT)gmx.de), Oct 21 2006
%E A122701 Missing a(0) inserted by _James C. McMahon_, Nov 09 2024