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.

A334639 Lexicographically earliest infinite sequence of distinct positive integers such that the result of the division of a(n+1) by a(n) starts with the decimal number [a.b] with a = the rightmost digit of a(n), b = the leftmost digit of a(n+1) and the decimal point = the comma between a(n) and a(n+1).

This page as a plain text file.
%I A334639 #16 Jan 09 2025 08:02:17
%S A334639 2,5,26,159,1447,10274,45206,280278,2298281,2757938,22615092,56537732,
%T A334639 118729239,1080436075,5942398413,18421435081,22105722098,179056348994,
%U A334639 859470475172,1804887997862,4331731194869,40718273231769,378679941055453,1173907817271905,6573883776722668,55878012102142678,469375301657998496,2910126870279590676,17751773908705503124,85208514761786414996
%N A334639 Lexicographically earliest infinite sequence of distinct positive integers such that the result of the division of a(n+1) by a(n) starts with the decimal number [a.b] with a = the rightmost digit of a(n), b = the leftmost digit of a(n+1) and the decimal point = the comma between a(n) and a(n+1).
%C A334639 Some light backtracking is needed sometimes to let the sequence go to infinity (especially when a new integer ends in zero: we then increase it by 1).
%D A334639 Eric Angelini, message to the Math-Fun mailing list on May 3rd 2020.
%H A334639 Jean-Marc Falcoz, <a href="/A334639/b334639.txt">Table of n, a(n) for n = 1..133</a>
%e A334639 The sequence starts with 2, 5, 26, 159, 1447, 10274, 45206,...
%e A334639 a(2) = 5 divided by a(1) = 2 is 2.5;
%e A334639 a(3) = 26 divided by a(2) = 5 starts with 5.2;
%e A334639 a(4) = 159 divided by a(3) = 26 starts with 6.1;
%e A334639 a(5) = 1447 divided by a(4) = 159 starts with 9.1;
%e A334639 a(6) = 10274 divided by a(5) = 1447 starts with 7.1;
%e A334639 a(7) = 45206 divided by a(6) = 10274 starts with 4.4; etc.
%Y A334639 Cf. A121805.
%K A334639 base,nonn
%O A334639 1,1
%A A334639 _Eric Angelini_ and _Jean-Marc Falcoz_, May 07 2020