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 A271420 #14 Jan 29 2025 18:36:55 %S A271420 0,0,0,1,0,1,0,1,2,1,0,1,0,1,2,1,0,1,3,1,2,1,0,1,0,1,2,1,0,1,4,1,2,1, %T A271420 3,1,0,1,2,1,0,1,0,1,2,1,0,1,3,1,2,1,0,1,5,1,2,1,4,1,0,1,2,1,3,1,0,1, %U A271420 2,1,0,1,6,1,2,1,0,1,3,1,2,1,0,1,4,1 %N A271420 Nonludicity of n. %C A271420 If n is ludic, a(n)=0; if n is nonludic, a(n) is the step at which n is rejected from the ludic number sieve. %H A271420 Max Barrentine, <a href="/A271420/b271420.txt">Table of n, a(n) for n = 1..10000</a> %F A271420 a(n) = (1-A192490(n)) * A260738(n). - _Antti Karttunen_, Sep 11 2016 %o A271420 (Scheme) (define (A271419 n) (* (- 1 (A192490 n)) (A260738 n))) ;; _Antti Karttunen_, Sep 11 2016 %Y A271420 Cf. A003309, A192490, A192607, A255127, A271419. %Y A271420 Cf. A265859 (analogous version for lucky numbers). %K A271420 nonn %O A271420 1,9 %A A271420 _Max Barrentine_, Apr 07 2016