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.

A328356 a(n) is the sum of all positive integers whose decimal expansion is up to n digits and does not contain the 0 digit.

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%I A328356 #19 Dec 12 2019 09:33:10
%S A328356 0,45,4500,409095,36855450,3317322645,298562027400,26870609370195,
%T A328356 2418355085455350,217651959870221745,19588676407933119300,
%U A328356 1762980876890499197295,158668278921733593899250,14280145102970321446216845,1285213059267457612117075200
%N A328356 a(n) is the sum of all positive integers whose decimal expansion is up to n digits and does not contain the 0 digit.
%H A328356 Colin Barker, <a href="/A328356/b328356.txt">Table of n, a(n) for n = 0..500</a>
%H A328356 Pierre-Alain Sallard, <a href="/A328356/a328356.pdf">Integer sequences A328348 and A328350 to A328356</a>
%H A328356 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (100,-909,810).
%F A328356 a(n) = (80*90^n - 89*9^n + 9) * 5 / 712.
%F A328356 a(n) = 91*a(n-1) - 90*a(n-2) + 45*9^(n-1) for n > 1.
%F A328356 G.f.: 45*x / ((1 - x)*(1 - 9*x)*(1 - 90*x)). - _Colin Barker_, Dec 10 2019
%e A328356 For n=2, the sum of all integers from 1 to 99 except those containing a zero (i.e., except multiples of 10: 10, 20, ..., 90) is equal to a(2) = 4500.
%e A328356 For n=3, the sum of all integers from 1 to 999 except those containing a zero is equal to a(3) = 409095.
%o A328356 (Python) [(80*90**n-89*9**n+9)*5//712 for n in range(20)]
%o A328356 (PARI) concat(0, Vec(45*x / ((1 - x)*(1 - 9*x)*(1 - 90*x)) + O(x^15))) \\ _Colin Barker_, Dec 10 2019
%Y A328356 Cf. A328348, A328350, A328351, A328352, A328353, A328354, A328355.
%K A328356 nonn,base,easy
%O A328356 0,2
%A A328356 _Pierre-Alain Sallard_, Dec 10 2019