

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, #d1, 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



