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A030292 Numbers k such that k^3 has at most two different digits. 7
0, 1, 2, 3, 4, 7, 10, 11, 20, 100, 200, 1000, 2000, 10000, 20000, 100000, 200000, 1000000, 2000000, 10000000, 20000000, 100000000, 200000000, 1000000000, 2000000000, 10000000000, 20000000000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Except for 0, 3, 4, 7, and 11, each term is of the form 10^x or 2*10^x. - Harvey P. Dale, Feb 05 2013

LINKS

Table of n, a(n) for n=1..27.

MAPLE

filter:= n -> nops(convert(convert(n^3, base, 10), set)) <= 2:

select(filter, [$1..10^5]); # Robert Israel, Nov 10 2014

MATHEMATICA

Join[Select[Range[0, 20], Count[DigitCount[#^3], 0]>7&], Flatten[Table[{10^n, 2*10^n}, {n, 2, 10}]]] (* Harvey P. Dale, Nov 23 2019 *)

PROG

(Python)

A030292_list, m = [0], [6, -6, 1, 0]

for n in range(1, 10**6+1):

    for i in range(3):

        m[i+1] += m[i]

    if len(set(str(m[-1]))) <= 2:

        A030292_list.append(n) # Chai Wah Wu, Nov 05 2014

(PARI) isok(n) = #Set(digits(n^3)) <= 2; \\ Michel Marcus, Nov 10 2014

(MAGMA) [n: n in [0..4000000] | #Set(Intseq(n^3)) le 2]; // Vincenzo Librandi, Nov 10 2014

CROSSREFS

Sequence in context: A342790 A347873 A139759 * A204231 A135419 A051914

Adjacent sequences:  A030289 A030290 A030291 * A030293 A030294 A030295

KEYWORD

nonn,base,nice

AUTHOR

Patrick De Geest

EXTENSIONS

More terms from Lior Manor, Jul 24 2001

STATUS

approved

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Last modified October 22 07:06 EDT 2021. Contains 348160 sequences. (Running on oeis4.)