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A317630 Lexicographically first sequence of different terms, starting with a(1) = 0 and showing a 1-step roller coaster of terms together with a 1-step roller coaster of digits (see the Comments section). 1
0, 2, 1, 4, 3, 6, 5, 8, 7, 80, 9, 13, 12, 15, 14, 17, 16, 19, 18, 24, 23, 26, 25, 28, 27, 34, 29, 36, 35, 38, 37, 45, 39, 47, 46, 49, 48, 57, 56, 59, 58, 68, 67, 120, 10, 21, 20, 31, 30, 40, 32, 42, 41, 50, 43, 52, 51, 54, 53, 61, 60, 63, 62, 65, 64, 71, 70, 73, 72, 75, 74, 81, 76, 83, 82, 85, 84, 87, 86, 91, 90, 93, 92, 95 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Every term a(n) > 0 of the sequence stands between two terms bigger than a(n) or between two terms smaller than a(n); this is also true for every digit d > 0 of the sequence that stands between two digits bigger than d or between two digits smaller than d.

LINKS

Lars Blomberg, Table of n, a(n) for n = 1..10000

EXAMPLE

The sequence starts with 0,2,1,4,3,6,5,8,7,80,9,13,12,15,14,17,16,19...

If we consider the terms, we see indeed that 0 < 2 > 1 < 4 > 3 < 6 > 5 < 8 > 7 < 80 > 9 < 13 > 12 < 15 > 14 < 17 > 16 < 19... and if we consider the digits, we see also that 0 < 2 > 1 < 4 > 3 < 6 > 5 < 8 > 7 < 8 > 0 < 9 > 1 < 3 > 1 < 2 > 1 < 5 > 1 < 4 > 1 < 7 > 1 < 6 > 1 < 9...

So no matter the elements considered (terms, digits), those elements seem to ride on a 1-step roller-coaster: up, down, up, down, up, etc.

CROSSREFS

Cf. A014681 (a 1-step roller coaster of terms only) and A317548 (a 1-step roller coaster of digits only).

Sequence in context: A243500 A026262 A026234 * A282651 A282665 A320283

Adjacent sequences:  A317627 A317628 A317629 * A317631 A317632 A317633

KEYWORD

nonn,base,look

AUTHOR

Eric Angelini and Jean-Marc Falcoz, Aug 02 2018

STATUS

approved

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Last modified April 24 19:49 EDT 2019. Contains 322446 sequences. (Running on oeis4.)