The OEIS is supported by the many generous donors to the OEIS Foundation. Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified September 21 17:55 EDT 2023. Contains 365503 sequences. (Running on oeis4.)