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 A381255 #12 Apr 22 2025 02:39:14 %S A381255 4,5,7,8,9,10,11,12,14,15,16,17,18,19,20,21,22,23,24,25,27,28,29,30, %T A381255 31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,52,53,54, %U A381255 55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74 %N A381255 Positive integers not of the form round(2^(k+2)/5). Complement of A007910. %F A381255 a(n) = m+1 if m>=floor((2^k+2)/5) otherwise a(n) = m where k = floor(log_2(5*n+3))+1 and m = n-2+k. %o A381255 (Python) %o A381255 def A381255(n): return (m:=n-2+(k:=(5*n+3).bit_length()))+(m>=((1<<k)|2)//5) %Y A381255 Cf. A007910. %K A381255 nonn %O A381255 1,1 %A A381255 _Chai Wah Wu_, Apr 21 2025