A252490 Numbers whose set of digits is simply connected, with 9 and 0 considered as neighbors.

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 21, 22, 23, 32, 33, 34, 43, 44, 45, 54, 55, 56, 65, 66, 67, 76, 77, 78, 87, 88, 89, 90, 98, 99, 100, 101, 102, 109, 110, 111, 112, 120, 121, 122, 123, 132, 190, 201, 210, 211, 212, 213, 221, 222, 223, 231, 232, 233, 234, 243, 312, 321, 322, 323, 324, 332, 333, 334, 342, 343, 344, 345, 354, 423, 432

Offset: 1

Author

M. F. Hasler, Dec 24 2014

Keywords

• nonn
• base
• easy

Comments

The set of digits must consist of a single run without "holes", but for a cyclic topology where 9 and 0 are seen as neighbors.

A superset of A134336. Namely, numbers in A134336 or such that the complement of their digits in {0,...,9} satisfies the criterion of A134336.

Links

• Danny Rorabaugh, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A032981, A050278, A033075 (a subsequence), A010785, A108965, A134336 (a subsequence).

Programs

PARI

is(n)=vecmax(if((d=Set(digits(n)))[1],d,d=setminus(vector(9,i,i),d)))-vecmin(d)==#d-1