cp's OEIS Frontend

A381980 a(n) is the first position where the digits of n occur simultaneously in the decimal expansions of Pi and e.

%I A381980 #20 Apr 02 2025 09:44:58
%S A381980 331,95,17,18,263,326,21,40,206,13,13422,428,500,6426,12896,11172,
%T A381980 17951,962,9710,2857,9261,4782,21688,17,26172,2526,2060,2900,5375,
%U A381980 6167,10097,13009,9287,12651,4175,840,38691,11997,14119,3519,4684,21785,7662,1798,1253,10869,9157,7216,3430,13191,5148,1843,10790
%N A381980 a(n) is the first position where the digits of n occur simultaneously in the decimal expansions of Pi and e.
%C A381980 The digits of the decimal expansions are numbered starting with 1 at the initial digits 3 (resp. 2).
%H A381980 Zhining Yang, <a href="/A381980/b381980.txt">Table of n, a(n) for n = 0..9999</a>
%e A381980 a(9) = 13 because the first "9" appears simultaneously in Pi and e at index 13:
%e A381980 Pi = 3.1415926535897932384626...
%e A381980      . ...........|.............
%e A381980  e = 2.7182818284590452353602...
%t A381980 pi=RealDigits[Pi,10,40000][[1]];
%t A381980 e=RealDigits[E,10,40000][[1]];
%t A381980 Table[Intersection[SequencePosition[pi,IntegerDigits[k]][[All,1]],SequencePosition[e,IntegerDigits[k]][[All,1]]][[1]],{k,0,52}]
%Y A381980 Cf. A000796 (Pi), A001113 (e).
%Y A381980 Cf. A032445 (positions in Pi), A088576 (positions in e).
%Y A381980 Cf. A052055 (positions in both Pi and e indicate a common digit).
%K A381980 nonn,base,easy
%O A381980 0,1
%A A381980 _Zhining Yang_, Mar 11 2025