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A023797
Katadromes: digits in base 16 are in strict descending order.
1
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 32, 33, 48, 49, 50, 64, 65, 66, 67, 80, 81, 82, 83, 84, 96, 97, 98, 99, 100, 101, 112, 113, 114, 115, 116, 117, 118, 128, 129, 130, 131, 132, 133, 134, 135, 144, 145, 146, 147, 148, 149, 150, 151, 152
OFFSET
1,3
COMMENTS
There are 65535 terms, with a(65535) = 18364758544493064720 = FEDCBA9876543210_16. - Michael S. Branicky, Feb 05 2024
LINKS
Eric Weisstein's World of Mathematics, Digit.
Eric Weisstein's World of Mathematics, Katadrome.
MATHEMATICA
Select[Range[0, 200], Max[Differences[IntegerDigits[#, 16]]]<0&] (* Harvey P. Dale, Oct 23 2022 *)
PROG
(Python)
from itertools import combinations, islice
def agen(): # generator of terms
yield 0
for d in range(1, 17):
yield from sorted(int("".join(c), 16) for c in combinations("FEDCBA9876543210", d) if c[0] != '0')
print(list(islice(agen(), 50))) # Michael S. Branicky, Feb 05 2024
CROSSREFS
Sequence in context: A023770 A371864 A357979 * A032951 A288139 A194897
KEYWORD
nonn,base,fini,easy
STATUS
approved