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A366966 Numbers whose difference between the largest and smallest digits is equal to 9.

%I A366966 #16 Nov 11 2023 00:15:31
%S A366966 90,109,190,209,290,309,390,409,490,509,590,609,690,709,790,809,890,
%T A366966 900,901,902,903,904,905,906,907,908,909,910,920,930,940,950,960,970,
%U A366966 980,990,1009,1019,1029,1039,1049,1059,1069,1079,1089,1090,1091,1092,1093,1094,1095
%N A366966 Numbers whose difference between the largest and smallest digits is equal to 9.
%C A366966 The number of n-digit terms of this sequence is 9*10^(n-1) - 17*9^(n-1) + 8^n.
%t A366966 Select[Range[1095],Max[d=IntegerDigits[#]]-Min[d]==9 &]
%o A366966 (Python)
%o A366966 def ok(n): return max(d:=list(map(int, str(n))))-min(d) == 9
%o A366966 print([k for k in range(1100) if ok(k)]) # _Michael S. Branicky_, Oct 30 2023
%o A366966 (Python)
%o A366966 from itertools import chain, count, islice, combinations_with_replacement
%o A366966 from sympy.utilities.iterables import multiset_permutations
%o A366966 def A366966_gen(): # generator of terms
%o A366966     return chain.from_iterable(sorted(int(''.join(str(d) for d in t)) for c in combinations_with_replacement(range(10),l) for t in multiset_permutations((0,9)+c) if t[0]) for l in count(0))
%o A366966 A366966_list = list(islice(A366966_gen(),30)) # _Chai Wah Wu_, Nov 10 2023
%o A366966 (PARI) isok(n) = my(d=digits(n)); vecmax(d) - vecmin(d) == 9; \\ _Michel Marcus_, Nov 05 2023
%Y A366966 Cf. A037904.
%Y A366966 Cf. A010785 (difference = 0), A366958 (difference = 1), A366959 (difference = 2), A366960 (difference = 3), A366961 (difference = 4), A366962 (difference = 5), A366963 (difference = 6), A366964 (difference = 7), A366965 (difference = 8).
%K A366966 nonn,base,easy
%O A366966 1,1
%A A366966 _Stefano Spezia_, Oct 30 2023