A023786 Katadromes: digits in base 4 are in strict descending order.

0, 1, 2, 3, 4, 8, 9, 12, 13, 14, 36, 52, 56, 57, 228

Offset

1,3

Comments

No more terms are possible because, although infinitely many numbers have base 4 digits in descending order, like 256, none beyond 228 can have them in strictly descending order. - Alonso del Arte, Feb 08 2019

Links

Table of n, a(n) for n=1..15.

Example

228 in base 4 is 3210. Since those digits are in strictly descending order, 228 is in the sequence.
229 in base 4 is 3211. Although those digits are in descending order, the repeated digit 1 means 229 is not in the sequence.

Mathematica

Select[Range[0, 255], Max[Differences[IntegerDigits[#, 4]]] < 0 &] (* Harvey P. Dale, Dec 15 2014 *)

Crossrefs

Cf. A023760, A031999.

Sequence in context: A184807 A032859 A032883 * A018231 A332622 A085256

Adjacent sequences: A023783 A023784 A023785 * A023787 A023788 A023789

Keyword

nonn,base,fini,full,easy

Author

Olivier Gérard

Status

approved