A107433 - OEIS

A107433

Slowest increasing sequence where some digit of a(n) and some digit of a(n+1) add up to 9.

0, 9, 10, 18, 19, 20, 27, 28, 31, 36, 37, 42, 45, 46, 50, 54, 55, 64, 65, 73, 76, 82, 87, 91, 98, 100, 108, 109, 110, 118, 119, 120, 127, 128, 129, 130, 136, 137, 138, 139, 140, 145, 146, 148, 149, 150, 154, 155, 158, 159, 160, 163, 164, 165, 168, 169, 170, 172, 173

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OFFSET

0,2

COMMENTS

Starting with another "seed" than 0 would produce another sequence.

LINKS

Robert Israel, Table of n, a(n) for n = 0..10000

EXAMPLE

After 28 we must have an integer containing a "7" (2+"7"=9) or a "1" (8+"1"=9). The smallest integer satisfying this constraint is 31 (and not 37 or 41 or any other containing a "7" or a "1")

MAPLE

f:= proc(n) local S, k;

S:= map(t -> 9-t, convert(convert(n, base, 10), set));

for k from n+1 do

if convert(convert(k, base, 10), set) intersect S <> {} then return k fi

end proc:

a[0]:= 0:

for n from 1 to 100 do a[n]:= f(a[n-1]) od:

seq(a[n], n=0..100); # Robert Israel, Feb 24 2017

CROSSREFS

Sequence in context: A088036 A217935 A100595 * A090570 A131417 A268135

Adjacent sequences: A107430 A107431 A107432 * A107434 A107435 A107436