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A371032 a(n) is the integer whose decimal digits are 0's or 1's in alternating runs of lengths n, n-1, n-2, ..., 3, 2, 1.

%I A371032 #37 Jul 09 2024 16:20:29
%S A371032 1,110,111001,1111000110,111110000111001,111111000001111000110,
%T A371032 1111111000000111110000111001,111111110000000111111000001111000110,
%U A371032 111111111000000001111111000000111110000111001,1111111111000000000111111110000000111111000001111000110
%N A371032 a(n) is the integer whose decimal digits are 0's or 1's in alternating runs of lengths n, n-1, n-2, ..., 3, 2, 1.
%F A371032 a(n) = A007088(A371033(n)). - _Michel Marcus_, Jul 09 2024
%F A371032 a(n) = (10^(n*(n+1)/2) - 1)/9 - a(n-1). - _Robert Israel_, Jul 09 2024
%e A371032 a(1) = 1 has runlength 1; a(2) = 110 has runlengths 2,1; a(3) = 111001 has runlengths 3,2,1.
%p A371032 f:= proc(n) option remember; (10^(n*(n+1)/2)-1)/9 - procname(n-1) end proc:
%p A371032 f(1):= 1:
%p A371032 map(f, [$1..30]); # _Robert Israel_, Jul 09 2024
%t A371032 Flatten[Table[Flatten[Map[ConstantArray[Mod[#, 2], n + 1 - #] &, Range[n]]], {n, 10}]]   (* _Peter J. C. Moses_, Mar 08 2024 *)
%o A371032 (Python)
%o A371032 def A371032(n):
%o A371032     c = 0
%o A371032     for i in range(n):
%o A371032         c = (m:=10**(n-i))*c
%o A371032         if i&1^1:
%o A371032             c += (m-1)//9
%o A371032     return c # _Chai Wah Wu_, Mar 18 2024
%Y A371032 Cf. A000217 (binary lengths), A007088, A065447, A371033 (decimal version).
%K A371032 nonn,base,easy
%O A371032 1,2
%A A371032 _Clark Kimberling_, Mar 09 2024
%E A371032 New name from _Michel Marcus_, Jul 09 2024