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 A258011 #15 Apr 29 2022 10:58:33
%S A258011 1,3,7,9,13,15,21,25,27,31,33,37,43,45,49,51,55,57,63,67,69,73,75,79,
%T A258011 85,87,91,93,97,99,105,109,111,115,117,121,127,129,133,135,139,141,
%U A258011 147,151,153,157,159,163,169,171,175,177,181,183,189,193,195,199,201,205,211,213,217,219,223,225,231,235,237,241,243,247,253,255
%N A258011 Numbers remaining after the third stage of Lucky sieve.
%C A258011 Equal to A047241 with its every seventh term (A258016) removed.
%C A258011 Numbers congruent to {1, 3, 7, 9, 13, 15, 21, 25, 27, 31, 33, 37} modulo 42. - _Jianing Song_, Apr 27 2022
%H A258011 Antti Karttunen, <a href="/A258011/b258011.txt">Table of n, a(n) for n = 1..10000</a>
%H A258011 <a href="/index/Rec#order_13">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,0,0,0,0,0,0,0,0,0,1,-1)
%F A258011 From _Jianing Song_, Apr 27 2022: (Start)
%F A258011 a(n) = a(n-12) + 42.
%F A258011 a(n) = a(n-1) + a(n-12) - a(n-13).
%F A258011 G.f.:(x+2*x^2+4*x^3+2*x^4+4*x^5+2*x^6+6*x^7+4*x^8+2*x^9+4*x^10+2*x^11+4*x^12+5*x^13)/(1-x-x^12+x^13). (End)
%p A258011 gf := (x*(1 + x*(2 + x*(4 + x*(2 + x*(4 + x*(2 + x*(6 + x*(4 + x*(2 + x*(4 + x*(2 + x*(4 + 5*x)))))))))))))/(1 - x*(1 + (1 - x)*x^11)): ser:= series(gf, x, 112):
%p A258011 seq(coeff(ser, x, k), k = 1..74); # _Peter Luschny_, Apr 29 2022
%o A258011 (Scheme)
%o A258011 (define (A258011 n) (A258207bi 3 n)) ;; A258207bi given in A258207.
%Y A258011 Row 3 of A258207.
%Y A258011 Setwise difference of A047241 \ A258016.
%Y A258011 Cf. also A260440 (Every ninth term).
%K A258011 nonn,easy
%O A258011 1,2
%A A258011 _Antti Karttunen_, Jul 27 2015