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A198486 Numbers with the property that all pairs of consecutive digits differ by 9. 1
1, 2, 3, 4, 5, 6, 7, 8, 9, 90, 909, 9090, 90909, 909090, 9090909, 90909090, 909090909, 9090909090, 90909090909, 909090909090, 9090909090909, 90909090909090, 909090909090909, 9090909090909090, 90909090909090909, 909090909090909090, 9090909090909090909 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

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

MATHEMATICA

t = {1, 2, 3, 4, 5, 6, 7, 8, 9}; Do[AppendTo[t, 10*t[[-1]]]; AppendTo[t, 10*t[[-1]] + 9], {9}]; t (* T. D. Noe, Oct 22 2013 *)

PROG

(Python)

def A198486():

    print('Numbers whose consecutive digits differ by 9')

    for i in range(1, 100001):

        b, n = True, i

        if n > 9:

            while n > 9:

                a = abs((n // 10) % 10 - n % 10)

                if a != 9: b = False

                n = n // 10

        if b: print(i, end=', ')

    return

CROSSREFS

Cf. A033075, A033088, A033081, A048406-A048410.

Sequence in context: A078188 A240511 A345406 * A061805 A280658 A061219

Adjacent sequences:  A198483 A198484 A198485 * A198487 A198488 A198489

KEYWORD

nonn,base

AUTHOR

Pieter Stadhouders, Oct 20 2013

EXTENSIONS

More terms from T. D. Noe, Oct 22 2013

STATUS

approved

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Last modified January 27 15:06 EST 2022. Contains 350607 sequences. (Running on oeis4.)