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 A347029 #22 Aug 21 2021 23:19:41
%S A347029 1,5,24,112,536,2576,12392,59610,286752,1379411,6635624,31920520,
%T A347029 153552936,738662923,3553321281,17093171649,82226315586,395547831245,
%U A347029 1902773895293,9153250784395,44031505860633,211812562992414,1018919543279305,4901489415968643,23578503968558227
%N A347029 a(n) = ceiling(e^(n*(Pi/2))).
%C A347029 Alternative formula for e^(n*Pi/2) is i^(-n*i), where i = sqrt(-1). Substitute 2i for n in each identity, resulting in e^(Pi*i) = -1; Euler's formula.
%C A347029 A121905 is the bisection of the sequence, ceiling(e^(n*Pi)).
%F A347029 a(n) = ceiling(e^(n*Pi/2)) = ceiling(i^(-n*i)).
%e A347029 a(5) = ceiling(e^(5*Pi/2)) = ceiling(i^(-5*i)) = 2576.
%t A347029 a[n_]:=Ceiling[Exp[n Pi/2]]; Table[a[n],{n,0,24}] (* _Stefano Spezia_, Aug 12 2021 *)
%o A347029 (PARI) a(n) = ceil(exp(n*Pi/2)); \\ _Michel Marcus_, Aug 12 2021
%Y A347029 Cf. A121905 (even bisection), A124507 (floor), A042972.
%K A347029 nonn
%O A347029 0,2
%A A347029 _Gary W. Adamson_, Aug 11 2021