cp's OEIS Frontend

A381509 Numbers whose nonzero digits are in nondecreasing order and any zeros appear at the end.

%I A381509 #16 Apr 18 2025 19:08:54
%S A381509 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,22,23,24,25,26,
%T A381509 27,28,29,30,33,34,35,36,37,38,39,40,44,45,46,47,48,49,50,55,56,57,58,
%U A381509 59,60,66,67,68,69,70,77,78,79,80,88,89,90,99,100,110,111,112,113,114,115,116,117
%N A381509 Numbers whose nonzero digits are in nondecreasing order and any zeros appear at the end.
%C A381509 This sequence includes all non-negative integers where non-zero digits (1-9) are in non-decreasing order and zeros are at the end.
%C A381509 Each term is a unique multiset of digits in canonical form.
%e A381509 112 is in the sequence because 1 <= 1 <= 2.
%e A381509 120 is in the sequence because 1 <= 2, then 0.
%e A381509 21 is not in the sequence because 2 > 1.
%e A381509 102 is not in the sequence because the zero is not at the end.
%o A381509 (Python)
%o A381509 from itertools import combinations_with_replacement as cwr, count, islice
%o A381509 def agen(): # generator of terms
%o A381509     yield 0
%o A381509     for d in count(1):
%o A381509         yield from sorted(int(f+"".join(mc)) for f in "123456789" for mc in cwr([str(i) for i in range(int(f), 10)]+["0"], d-1))
%o A381509 print(list(islice(agen(), 1000))) # _Michael S. Branicky_, Apr 11 2025
%Y A381509 A variant of A179239.
%K A381509 nonn,base,easy
%O A381509 1,3
%A A381509 _Keenin D. Krehbiel_, Feb 25 2025