# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/

Search: id:a339700
Showing 1-1 of 1

%I A339700 #26 Jan 08 2021 22:16:18
%S A339700 71,77,47,61,70,52,62,99,136,190,246,263,306,589,882,1085,1838,2059,
%T A339700 2308,2869,5886,8689,10800,18098,20268,20896,28608,58880,86886,106898,
%U A339700 180889,200858,208698,283888,588868,868880,1068889,1808886,2008086,2086868,2809888,5888808,8688868,10688886,18088880
%N A339700 a(n) is the n-th nonnegative number to light exactly n segments when displayed on a calculator.
%C A339700 a(n) is undefined for n<5, as there are no numbers with 1 segment, 1 with 2 segments, 1 with 3 segments, and 2 with 4 segments. If 0 is excluded as a valid input - so the series would refer to "the n-th positive number" - then a(6) would be 111 rather than 77.
%H A339700 Graham Holmes, <a href="/A339700/b339700.txt">Table of n, a(n) for n = 5..82</a>
%H A339700 <a href="/index/Ca#calculatordisplay">Index entries for sequences related to calculator display</a>
%e A339700 For n=7, 47 is the 7th positive number to light 7 segments, after 8, 12, 13, 15, 21, and 31.
%o A339700 (JavaScript) s=[6,2,5,5,4,5,6,3,7,6];p=[];a=[];for(i=2;i<=100;i++)p[i]=0;for(i=1;i<=1000000;i++){d=i;n=0;do{x=d%10;n+=s[x];d=(d-x)/10;}while(d>0)p[n]++;if(p[n]==n)a[n]=i;}for(c=2;c<=40;c++)document.write(c+": "+a[c]+"<br>");
%Y A339700 Cf. A006942 (segments lit), A216261, A331529.
%K A339700 nonn,base
%O A339700 5,1
%A A339700 _Graham Holmes_, Dec 13 2020

# Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE