login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A082927 Numbers in which at least one pair of adjacent digits differ by 1. 4
10, 12, 21, 23, 32, 34, 43, 45, 54, 56, 65, 67, 76, 78, 87, 89, 98, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 112, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 132, 134, 143, 145, 154, 156, 165, 167, 176, 178, 187, 189, 198, 201, 210, 211, 212, 213 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..57.

FORMULA

a(n) = n + O(x^0.915), where the exponent is the log(k)/log(10) with k the largest root of x^5 - 9x^4 + 4x^3 + 21x^2 - 9x - 5. - Charles R Greathouse IV, Mar 11 2014

EXAMPLE

1998 is a term because 8 and 9 differ by 1.

MATHEMATICA

Select[Range[250], MemberQ[Abs[Differences[IntegerDigits[#]]], 1]&] (* Harvey P. Dale, Apr 07 2018 *)

PROG

(PARI) isok(n) = (d = digits(n)) && (sum(i=1, #d-1, abs(d[i] - d[i+1])==1) >= 1); \\ Michel Marcus, Mar 11 2014

CROSSREFS

Sequence in context: A337866 A357045 A320170 * A108965 A341002 A175885

Adjacent sequences: A082924 A082925 A082926 * A082928 A082929 A082930

KEYWORD

base,easy,nonn

AUTHOR

Anonymous, Apr 15 2003

EXTENSIONS

120 added by Zak Seidov, Mar 11 2014

Name clarified by Jon E. Schoenfield, Oct 29 2022

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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified January 27 10:15 EST 2023. Contains 359838 sequences. (Running on oeis4.)