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 A303029 #39 Dec 25 2022 08:30:44
%S A303029 3,1,4,8,8,21,21,62,128,190,430,831,1451,3030,6143,12286,24361,48850,
%T A303029 85497,134347,268694,583208,1071746,2192342,3264088,7514425,14042601,
%U A303029 24821114,46378140,99867664,171066918,270934582,634625444,1272514976,2449009584,0,2449009584
%N A303029 From a riddle, see Puzzling.SE link.
%H A303029 Rémy Sigrist, <a href="/A303029/b303029.txt">Table of n, a(n) for n = 0..400</a>
%H A303029 Puzzling.SE, <a href="https://puzzling.stackexchange.com/questions/69357/what-number-comes-next/69391">What number comes next?</a>
%F A303029 a(n) = 0 for all n > 362. - _Alois P. Heinz_, Aug 18 2018
%F A303029 From _Jianing Song_, Dec 25 2022: (Start)
%F A303029 Let d_k = A000796(k+1) be the k-th digit of Pi, then a(n) = a(n-1) + a(n-2) + ... + a(n-d_{n-3}) for n >= 3.
%F A303029 If there exists consecutive 9 digits ...d_{k}d_{k+1}...d_{k+8}... of Pi such that d_{k+i} <= i for i = 0..8, then a(n) = 0 for all n >= k+3. The 360th to 368th digits of Pi are ...001133053..., so a(n) = 0 for all n >= 363. (End)
%e A303029 a(0,1,2) = 3,1,4
%e A303029 To continue, we use the decimal expansion of Pi = 3.14159...:
%e A303029 a(3) = 3+1+4 (3-bonacci) = 8
%e A303029 a(4) = 8 (1-bonacci) = 8
%e A303029 a(5) = 1+4+8+8 (4-bonacci) = 21
%e A303029 a(6) = 21 (1-bonacci) = 21
%e A303029 a(7) = 21+21+8+8+4 (5-bonacci) = 62
%e A303029 ...
%Y A303029 Cf. A000796.
%K A303029 nonn,base,easy,less
%O A303029 0,1
%A A303029 _David F. Marrs_, Aug 16 2018