A119204 - OEIS

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A119204

Triangular numbers composed of digits {4,5,7}.

2

45, 55, 5747745, 744574755, 77545447574475, 4745745457757444544544575, 44477447457545755547775754555, 547457575775574544754447747777455

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

a(8) > 10^40. - Tyler Busby, Mar 28 2023

LINKS

Table of n, a(n) for n=1..8.

Giovanni Resta, Tridigital Triangular Numbers.

FORMULA

a(n) = A000217(A119205(n)). - Jon E. Schoenfield, Mar 27 2023

CROSSREFS

Cf. A000217, A053951, A119205. See A119033 for a table of cross-references.

Sequence in context: A068812 A119071 A119158 * A119206 A060463 A206024

Adjacent sequences: A119201 A119202 A119203 * A119205 A119206 A119207

KEYWORD

nonn,base,more

AUTHOR

Giovanni Resta, May 10 2006

EXTENSIONS

a(8) from Tyler Busby, Mar 28 2023

STATUS

approved