cp's OEIS Frontend

A256955 Decimal expansion of the sum of the reciprocals of all positive integers with digits in strictly decreasing order (there are exactly 1022 such integers - see A009995).

%I A256955 #19 Jul 02 2025 18:46:21
%S A256955 3,8,9,8,4,0,6,7,3,6,9,9,9,0,5,3,6,4,7,3,4,4,5,9,6,2,6,0,7,2,4,8,7,3,
%T A256955 7,8,3,8,4,9,6,0,2,0,4,7,9,0,3,4,1,2,5,7,4,6,8,2,7,8,5,8,6,5,1,0,8,7,
%U A256955 8,8,6,0,4,6,9,5,6,4,8,6,3,6,3,4,7,8,6,5,6,0,1,0,6,5,8,2,6,8,8,7,7,2,8,9
%N A256955 Decimal expansion of the sum of the reciprocals of all positive integers with digits in strictly decreasing order (there are exactly 1022 such integers - see A009995).
%C A256955 Since there are only finitely many such numbers, the sum is rational.
%e A256955 2009584261...2790050791 (1292 digits)
%e A256955 -------------------------------------- = 3.8984067369990536473445962607....
%e A256955 5154886078...0332960000 (1291 digits)
%o A256955 (Magma) m:=&+[1/k: k in [A009995(n)]]; Reverse(Intseq(Floor(10^104*m)));
%Y A256955 Cf. A009995, A117914.
%K A256955 nonn,base,cons
%O A256955 1,1
%A A256955 _Jaroslav Krizek_, Apr 19 2015