A220136 - OEIS

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A220136

Number of ways that a number n can be written as ddd...d where d is a digit in base b with 1 < b < n-1.

0, 0, 0, 0, 0, 0, 1, 1, 0, 1, 0, 1, 1, 1, 2, 1, 0, 2, 0, 1, 2, 1, 0, 3, 0, 2, 1, 2, 0, 2, 2, 2, 1, 1, 1, 3, 0, 1, 1, 4, 0, 3, 1, 2, 2, 1, 0, 4, 0, 2, 1, 2, 0, 3, 1, 2, 2, 1, 0, 5, 0, 2, 4, 2, 1, 3, 0, 2, 1, 3, 0, 4, 1, 1, 2, 2, 1, 3, 0, 5, 1, 1, 0, 5, 2, 2, 1

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OFFSET

1,15

COMMENTS

When a(n) > 0, n is called Brazilian (A125134). The first number having exactly k representations is A284758(k) for k >= 0 or A066460(k+1) for k > 0. - Bernard Schott, Apr 08 2017

LINKS

T. D. Noe, Table of n, a(n) for n = 1..10000

MATHEMATICA

brazBases[n_] := Select[Range[2, n - 2], Length[Union[IntegerDigits[n, #]]] == 1 &]; Table[Length[brazBases[n]], {n, 100}]

PROG

(PARI) a(n) = sum(i=2, n-2, #vecsort(digits(n, i), , 8)==1) \\ David A. Corneth, Apr 08 2017

CROSSREFS

Cf. A066460, A125134, A284758.

Sequence in context: A091392 A036577 A317189 * A322454 A133693 A002325

Adjacent sequences: A220133 A220134 A220135 * A220137 A220138 A220139

KEYWORD

nonn

AUTHOR

T. D. Noe, Dec 26 2012

STATUS

approved