A031152 -id:A031152

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page 1

A031154

Numbers k such that k^2 contains only digits {2,4,5}.

+10
2

2, 5, 15, 65, 235, 665, 2132, 2335, 6515, 6665, 23335, 47162, 66515, 66665, 67485, 233335, 235065, 666515, 666665, 2333335, 6666515, 6666665, 23333335, 64980962, 66666515, 66666665, 233333335, 666666515, 666666665, 2333333335, 5044357665

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

OFFSET

1,1

LINKS

Zhao Hui Du, Table of n, a(n) for n = 1..106

Patrick De Geest, Squares containing at most three distinct digits, Index entries for related sequences

Author?, Source(txt)

CROSSREFS

Cf. A031152.

KEYWORD

nonn,base

AUTHOR

Patrick De Geest

EXTENSIONS

Extended and corrected by author Mar 15 2000

More terms from C. Ronaldo (aga_new_ac(AT)hotmail.com), Jan 03 2005

STATUS

approved

A119158

Triangular numbers composed of digits {2,4,5}.

+10
2

45, 55, 25425, 255255, 22542255, 244525555, 2245524452445, 2445254445525, 5255545252454245, 444222245455224445, 4544525455555255444225, 5554545454254522254255544522452525245

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

OFFSET

1,1

COMMENTS

a(13) > 10^40.

LINKS

Table of n, a(n) for n=1..12.

G. Resta, Tridigital Triangular Numbers.

FORMULA

a(n) = A000217(A119159(n)).

CROSSREFS

Cf. A000217, A031152, A119159. See A119033 for a table of cross-references.