A119087 Triangular numbers composed of digits {0,6,7}.

6, 66, 666, 6670, 66066, 600060, 67007676, 670677000, 66067760760, 76666077676, 76670776666, 660067006660776, 7600067000007076, 6700677067067607000, 60660060606000770770776700, 776600760606070666600067770, 7766770606766667760666707766

Offset

1,1

Links

Table of n, a(n) for n=1..17.

Giovanni Resta, Tridigital Triangular Numbers.

Formula

a(n) = A000217(A119088(n)). - Tyler Busby, Mar 31 2023

Crossrefs

Cf. A000217, A058450, A119088. See A119033 for a table of cross-references.

Sequence in context: A002280 A073548 A073549 * A119212 A068643 A119053

Adjacent sequences: A119084 A119085 A119086 * A119088 A119089 A119090

Keyword

nonn,base

Author

Giovanni Resta, May 10 2006

Extensions

a(16)-a(17) from Tyler Busby, Mar 23 2023

Status

approved