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A290950 Positive integers whose digits are in increasing order and whose successive digits differ by exactly 2. 0
1, 2, 3, 4, 5, 6, 7, 8, 9, 13, 24, 35, 46, 57, 68, 79, 135, 246, 357, 468, 579, 1357, 2468, 3579, 13579 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

There are 11 - 2*k terms of the sequence with k digits, 1 <= k <= 5.

LINKS

Table of n, a(n) for n=1..25.

FORMULA

The terms can be described by the following linear equations:

for  1 <= n <=  9, a(n) =        n;

for 10 <= n <= 16, a(n) =    11*(n -  9) +    2;

for 17 <= n <= 21, a(n) =   111*(n - 16) +   24;

for 22 <= n <= 24, a(n) =  1111*(n - 21) +  246;

for       n  = 25, a(n) = 11111*(n - 24) + 2468.

MATHEMATICA

Select[Range[10^5], Or[Length@ # == 1, Union@ Differences@ # == {2}] &@ IntegerDigits@ # &] (* Michael De Vlieger, Aug 15 2017 *)

CROSSREFS

Sequence in context: A034294 A304246 A271837 * A032577 A244155 A066310

Adjacent sequences:  A290947 A290948 A290949 * A290951 A290952 A290953

KEYWORD

nonn,base,fini,full

AUTHOR

Enrique Navarrete, Aug 14 2017

STATUS

approved

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Last modified September 19 16:34 EDT 2021. Contains 347564 sequences. (Running on oeis4.)