The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A039088 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A039088

Numbers whose base-9 representation has the same number of 1's and 6's.
(history; published version)

#16 by Joerg Arndt at Fri Jun 25 01:42:40 EDT 2021

STATUS

proposed

approved

#15 by Michel Marcus at Fri Jun 25 00:31:43 EDT 2021

STATUS

editing

proposed

#14 by Michel Marcus at Fri Jun 25 00:31:41 EDT 2021

CROSSREFS

Cf. A007095.

STATUS

proposed

editing

#13 by Jon E. Schoenfield at Thu Jun 24 23:56:54 EDT 2021

STATUS

editing

proposed

#12 by Jon E. Schoenfield at Thu Jun 24 23:56:53 EDT 2021

NAME

Numbers n such that whose base-9 representation in base 9 has the same number of 1's and 6's.

STATUS

approved

editing

#11 by Bruno Berselli at Tue Mar 13 04:18:24 EDT 2018

STATUS

proposed

approved

#10 by Michel Marcus at Tue Mar 13 02:13:19 EDT 2018

STATUS

editing

proposed

#9 by Michel Marcus at Tue Mar 13 02:13:15 EDT 2018

PROG

(PARI) isok(n) = {my(d = digits(n, 9)); #select(x->(x==1), d) == #select(x->(x==6), d); } \\ Michel Marcus, Mar 13 2018

STATUS

proposed

editing

#8 by Robert Israel at Tue Mar 13 00:30:34 EDT 2018

STATUS

editing

proposed

#7 by Robert Israel at Tue Mar 13 00:30:28 EDT 2018

LINKS

Robert Israel, <a href="/A039088/b039088.txt">Table of n, a(n) for n = 1..10000</a>

MAPLE

filter:= proc(n) local L;

L:= convert(n, base, 9);

numboccur(1, L) = numboccur(6, L)

end proc:

select(filter, [$0..1000]); # Robert Israel, Mar 13 2018

STATUS

approved

editing