A218397 Triangular numbers composed of digits {0,2,7}.

70007020020, 27272070272700, 20720272227227700077007700020, 22200020770272007007202277772702722200

Offset

1,1

Comments

a(5) > 10^40.

Links

Table of n, a(n) for n=1..4.

Giovanni Resta, Tridigital Triangular Numbers.

Formula

a(n) = A000217(A218398(n)).

Crossrefs

Cf. A000217, A218398. See A119033 for a table of cross-references.

Sequence in context: A139572 A321284 A186095 * A103617 A213334 A211417

Adjacent sequences: A218394 A218395 A218396 * A218398 A218399 A218400

Keyword

base,nonn,more

Author

Max Alekseyev, Oct 28 2012

Status

approved