A125289 - OEIS

A125289

Numbers with unique nonzero digit in decimal representation.

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 20, 22, 30, 33, 40, 44, 50, 55, 60, 66, 70, 77, 80, 88, 90, 99, 100, 101, 110, 111, 200, 202, 220, 222, 300, 303, 330, 333, 400, 404, 440, 444, 500, 505, 550, 555, 600, 606, 660, 666, 700, 707, 770, 777, 800, 808, 880, 888, 900, 909

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

OFFSET

1,2

COMMENTS

A043537(a(n)) <= 2.

A043537(A004719(a(n))) = 1: A004719(a(n)) is a repdigit number, see A010785;

also numbers having exactly one partition into digit values of their decimal representations: A061827(a(n))=1.

LINKS

Rémy Sigrist, Table of n, a(n) for n = 1..9207

Eric Weisstein's World of Mathematics, Repeating Decimal

Eric Weisstein's World of Mathematics, Repdigit

PROG

(Python)

A125289_list = [n for n in range(10**4) if len(set(str(n))-{'0'})==1]

# Chai Wah Wu, Jan 04 2015

(PARI) is(n, base=10) = #Set(select(sign, digits(n, base)))==1 \\ Rémy Sigrist, Mar 28 2020

(PARI) a(n, base=10) = { for (w=0, oo, if (n<=(base-1)*2^w, my (d=1+(n-1)\2^w, k=2^w+(n-1)%(2^w)); return (d*fromdigits(binary(k), base)), n -= (base-1)*2^w)) } \\ Rémy Sigrist, Mar 28 2020

CROSSREFS

Cf. A125292.

Sequence in context: A169824 A325152 A061917 * A180482 A193460 A114801

Adjacent sequences: A125286 A125287 A125288 * A125290 A125291 A125292

KEYWORD

nonn,base

AUTHOR

Reinhard Zumkeller, Nov 26 2006

STATUS

approved