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 A306389 #24 Dec 04 2024 18:50:47
%S A306389 -3,-2,-6,-5,-10,-1,-3,3,-2,1,-4,4,-5,2,-7,-4,-6,-3,-11,-7,-13,-11,
%T A306389 -17,-13,-16,-13,-21,-18,-20,-13,-22,-17,-17,-15,-23,-15,-19,-18,-27,
%U A306389 -20,-21,-15,-24,-21,-30,-21,-24,-17,-22,-21,-21,-16,-24,-22,-22,-13,-20,-16,-25,-21,-25,-20,-29,-27,-30,-30,-37,-29,-30,-24,-28
%N A306389 Partial sums of (k-th digit of decimal expansion of Pi multiplied by (-1)^k).
%C A306389 a(n) > 0 for n = 8, 10, 12, 14, 16124, 16126, ... and a(n) = 0 for n = 16120, 16161, 16937, ... - _Michel Marcus_, Feb 13 2019
%F A306389 a(n) = Sum_{k=1..n} (-1)^k*A000796(k).
%F A306389 a(n) = Sum_{k=1..floor(n/2)} A099817(k) - Sum_{k=1..floor((n+1)/2)} A099816(k). - _Michel Marcus_, Feb 16 2019
%t A306389 Accumulate@ MapIndexed[(-1)^First[#2]*#1 &, First@ RealDigits[Pi, 10, 71]] (* _Michael De Vlieger_, Feb 15 2019 *)
%Y A306389 Cf. A000796, A046974, A099816, A099817.
%K A306389 sign,base,easy
%O A306389 1,1
%A A306389 _Luca Petrone_, Feb 12 2019