A082927 Numbers in which at least one pair of adjacent digits differ by 1.

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

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 A366958 A341002

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