The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A119043

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Showing entries 1-10 | older changes

A119043

Triangular numbers composed of digits {0,1,7}.
(history; published version)

#13 by Michael De Vlieger at Fri Mar 31 13:21:15 EDT 2023

STATUS

reviewed

approved

#12 by Andrew Howroyd at Fri Mar 31 13:16:49 EDT 2023

STATUS

proposed

reviewed

#11 by Tyler Busby at Fri Mar 31 13:15:15 EDT 2023

STATUS

editing

proposed

#10 by Tyler Busby at Fri Mar 31 13:15:06 EDT 2023

LINKS

G. Giovanni Resta, <a href="http://www.numbersaplenty.com/tr/tr017.html">Tridigital Triangular Numbers</a>.

FORMULA

a(n) = A000217(A119044(n)). - Tyler Busby, Mar 31 2023

STATUS

approved

editing

#9 by Alois P. Heinz at Wed Mar 22 16:06:05 EDT 2023

STATUS

proposed

approved

#8 by Tyler Busby at Wed Mar 22 16:05:46 EDT 2023

STATUS

editing

proposed

#7 by Tyler Busby at Wed Mar 22 16:05:44 EDT 2023

DATA

1, 10, 171, 1711, 1770, 10011, 111117701071, 17170010070077710, 101711101707777771, 701000700077010700, 1701111717707771071, 10010107100007777700, 101770070070071771070, 170107111111710707070, 1177170070777107111711, 70071707101001717077017171

EXTENSIONS

a(15)-a(16) from Tyler Busby, Mar 22 2023

STATUS

approved

editing

#6 by Harvey P. Dale at Tue Sep 06 12:12:32 EDT 2022

STATUS

editing

approved

#5 by Harvey P. Dale at Tue Sep 06 12:12:29 EDT 2022

MATHEMATICA

Select[FromDigits/@Tuples[{0, 1, 7}, 12], OddQ[Sqrt[8#+1]]&] (* The program generates the first 8 terms of the sequence. *) (* Harvey P. Dale, Sep 06 2022 *)

STATUS

approved

editing

#4 by Giovanni Resta at Tue Oct 06 09:00:08 EDT 2015

STATUS

editing

approved