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 A335984 #25 May 23 2021 03:24:03 %S A335984 4,5,7,9,11,19,21,31,33,39,49,51,81,99,101,123,129,159,171,177,189, %T A335984 231,291,441,879,1011,2751 %N A335984 Numbers m such that more than half the distinct positive terms of the sequence -k^2 + m*k - 1 are primes. %C A335984 Numbers m such that more than half the distinct terms in row m-2 of the triangular array A059036 are prime. %C A335984 All positive terms of the sequence are prime for m = 1, 2, 4, 5, 9 and 21. %C A335984 There are no more terms below 200000. - _Pontus von Brömssen_, Jul 06 2020 %C A335984 Numbers m such that A109909(m) > m/4. - _Pontus von Brömssen_, May 09 2021 %e A335984 7 is in the sequence because with g(k) = -k^2+7*k-1, the positive terms of the sequence g(k) are 5=g(1), 9=g(2) and 11=g(3), and two out of the three (5 and 9) are prime. %p A335984 filter:= n -> nops(select(isprime, [seq(n*x-x^2-1,x=1..n/2)])) > 1/2*floor(n/2): %p A335984 select(filter, [$1..10000]); %Y A335984 Cf. A059036, A109909. %K A335984 nonn,more %O A335984 1,1 %A A335984 _Robert Israel_, Jul 03 2020