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 A363653 #10 Jul 06 2023 22:05:59
%S A363653 1,3,1,4,2,6,4,8,5,1,3,9,7,3,7,2,4,10,8,2,6,2,4,12,9,5,1,7,5,13,11,5,
%T A363653 1,5,1,10,8,4,8,16,14,6,4,10,4,8,6,16,13,7,3,9,7,15,11,3,7,3,1,13,11,
%U A363653 7,1,8,4,12,10,4,8,16,14,2,4,8,2,8,4,12,10,20,15,11,9,21
%N A363653 a(1) = 1; for n > 1, a(n) = a(n-1) - A000005(n) if a(n) strictly positive, else a(n) = a(n-1) + A000005(n).
%C A363653 Variation on Recamán's sequence A005132.
%e A363653 a(1) = 1
%e A363653 a(2) = 1 + A000005(2) = 3
%t A363653 a[1] = 1; a[n_] := a[n] = Module[{d = DivisorSigma[0, n]}, If[a[n - 1] > d, a[n - 1] - d, a[n - 1] + d]]; Array[a, 100] (* _Amiram Eldar_, Jun 13 2023 *)
%Y A363653 Cf. A000005, A005132, A008343, A008344, A046901, A063733, A336760.
%K A363653 nonn
%O A363653 1,2
%A A363653 _Ctibor O. Zizka_, Jun 13 2023