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A136970 Numbers k such that k and k^2 use only the digits 1, 2, 3, 4 and 7. 1
1, 2, 11, 12, 21, 111, 132, 271, 421, 1111, 1171, 1312, 1332, 2171, 13332, 34311, 34312, 133332, 371111, 417412, 421111, 473421, 1214171, 1333332, 3337271, 3427421, 12137271, 13333332, 121337271, 131423412, 133333332, 177232171, 217433311, 333432412, 334232171, 337227421, 377774171, 473743311, 1114142412, 1114142421, 1114144171 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Generated with DrScheme.

LINKS

Jonathan Wellons, Table of n, a(n) for n = 1..149

J. Wellons, Tables of Shared Digits

EXAMPLE

217134132142421^2 = 47147231341242344447427741241.

MATHEMATICA

Table[With[{c={1, 2, 3, 4, 7}}, Select[FromDigits/@Tuples[c, n], SubsetQ[ c, IntegerDigits[ #^2]]&]], {n, 10}]//Flatten (* Harvey P. Dale, Feb 24 2016 *) (* Harvey P. Dale, Feb 24 2016 *)

CROSSREFS

Sequence in context: A038113 A089600 A114034 * A136967 A213975 A137001

Adjacent sequences:  A136967 A136968 A136969 * A136971 A136972 A136973

KEYWORD

base,nonn

AUTHOR

Jonathan Wellons (wellons(AT)gmail.com), Jan 22 2008

STATUS

approved

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Last modified January 19 06:18 EST 2022. Contains 350464 sequences. (Running on oeis4.)