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 A101623 #11 Aug 01 2025 11:09:34
%S A101623 1,1,11,1,111,101,1011,1,10111,10101,111011,10001,1100111,1000101,
%T A101623 10001011,1,100010111,100010101,1100111011,100010001,11101100111,
%U A101623 10101000101,101110001011,100000001,1011000010111,1010000010101,11100000111011,1000000010001,110000001100111
%N A101623 Modular binomial transform of 10^n.
%F A101623 a(n) = Sum_{k=0..floor(n/2)} mod(binomial(n-k, k), 2)*10^k.
%F A101623 a(n) = Sum_{k=0..n} mod(binomial(k, n-k), 2)*10^(n-k).
%o A101623 (Python)
%o A101623 def A101623(n): return sum(int(not k & ~(n-k))*10**k for k in range((n>>1)+1)) # _Chai Wah Wu_, Jul 30 2025
%o A101623 (PARI) a(n) = sum(k=0, n, lift(Mod(binomial(k, n-k), 2))*10^(n-k)); \\ _Michel Marcus_, Jul 31 2025
%Y A101623 A101624 in binary.
%K A101623 easy,nonn
%O A101623 0,3
%A A101623 _Paul Barry_, Dec 10 2004
%E A101623 More terms from _Michel Marcus_, Jul 31 2025