This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A382723 #13 Aug 12 2025 02:41:06
%S A382723 1,2,3,4,3,6,6,8,3,6,8,12,6,12,12,16,3,6,8,12,8,16,16,24,6,12,16,24,
%T A382723 12,24,24,32,3,6,8,12,8,16,16,24,8,16,20,32,16,32,32,48,6,12,16,24,16,
%U A382723 32,32,48,12,24,32,48,24,48,48,64,3,6,8,12,8,16,16,24,8,16,20,32,16,32,32,48,8
%N A382723 Number of entries in the n-th row of Pascal's triangle not divisible by 4.
%F A382723 a(n) = (A033264(n)+2)*2^(A000120(n)-1). - _Chai Wah Wu_, Aug 10 2025
%o A382723 (PARI) a(n) = sum(k=0, n, (binomial(n, k) % 4) != 0); \\ _Michel Marcus_, Apr 23 2025
%o A382723 (Python)
%o A382723 def A382723(n): return bin(n)[2:].count('10')+2<<n.bit_count()-1 if n else 1 # _Chai Wah Wu_, Aug 10 2025
%Y A382723 Cf. A000120, A001316, A006047, A033264, A194459, A382720-A382725.
%K A382723 nonn
%O A382723 0,2
%A A382723 _N. J. A. Sloane_, Apr 23 2025