cp's OEIS Frontend

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.

A374380 Numbers b such that the base-b expansion of Pi has two equal digits immediately after the radix point.

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%I A374380 #28 Jul 31 2024 11:53:16
%S A374380 2,8,114,227,340,453,566,679,33103,66318,265382,1360121,1725034,
%T A374380 25510583,78256780,209259756,340262732,1151791170,1963319608,
%U A374380 6701487260,13402974519,20104461778,26805949037,33507436296,40208923555,46910410814,53611898073,574364584668
%N A374380 Numbers b such that the base-b expansion of Pi has two equal digits immediately after the radix point.
%C A374380 The probability that this occurs in a random base-b number is 1/b, so the divergence of the harmonic series suggests this sequence is infinite.  a(28) = 574364584668 is the largest term < 10^12.
%C A374380 If 1 is added to terms of A002486, many of the resulting numbers (roughly 60%) are terms of this sequence. - _Mike Keith_, Jul 28 2024
%e A374380 2 is a term since Pi in base 2 is 11.00... which has two equal digits 0,0.
%e A374380 114 is a term since Pi in base 114 is 3.(16)(16)... which has two equal "digits" 16 and 16.
%Y A374380 Cf. A000796 (Pi), A336017 (second digit after radix point), A002486 (continued fraction convergent denominators).
%K A374380 nonn
%O A374380 1,1
%A A374380 _Mike Keith_, Jul 06 2024