A152054 - OEIS

A152054

Bouncy numbers (numbers whose digits are in neither increasing nor decreasing order).

101, 102, 103, 104, 105, 106, 107, 108, 109, 120, 121, 130, 131, 132, 140, 141, 142, 143, 150, 151, 152, 153, 154, 160, 161, 162, 163, 164, 165, 170, 171, 172, 173, 174, 175, 176, 180, 181, 182, 183, 184, 185, 186, 187, 190, 191, 192, 193, 194, 195, 196

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

OFFSET

1,1

COMMENTS

Complement of union ofA009994andA009996.-Ray Chandler,Oct 25 2011

Number of n-digit bouncy numbers is 9*10^(n-1) - (n+18)*binomial(n+8, 8)/9 + 10. -Altug Alkan,Oct 02 2018

LINKS

David F. Marrs,Table of n, a(n) for n = 1..10000

Project Euler,Non-bouncy numbers Problem 113

MATHEMATICA

Select[Range[0, 200],!LessEqual@@IntegerDigits[#] &&!GreaterEqual@@IntegerDigits[#]&] (*Ray Chandler,Oct 25 2011 *)

bnQ[n_]:=Module[{didn=Differences[IntegerDigits[n]]}, Count[didn, _?(#>0&)]>0 && Count[didn, _?(#<0&)]>0]; Select[Range[100, 200], bnQ] (*Harvey P. Dale,Jun 13 2020 *)

PROG

(Python)

a = 1

b = 100

while a!= 51:

if str(b)!= ''.join(sorted(str(b))) and str(b)!= ''.join(sorted(str(b)))[::-1]:

print(b)

a += 1

b += 1

#David F. Marrs,Sep 25 2018

(Python)

from itertools import count, islice