%I #26 Jan 02 2023 09:01:48
%S 139,1313,5359,15365,34229,68385,120421,200839,312057,468827,669591,
%T 943175,1274089,1701441,2216841,2856379,3594651,4510437,5541135,
%U 6788823,8195941,9845089,11670925,13842429,16191555
%N a(n) is the number of reducible monic quintic polynomials (x^5 + r*x^4 + s*x^3 + t*x^2 + u*x + v) with integer coefficients bounded by naïve height n (abs(r), abs(s), abs(t), abs(u), abs(v) <= n).
%o (PARI)
%o { a(n) = \\ A358400
%o my( ct = 0 );
%o for (c1 = -n, n,
%o for (c2 = -n, n,
%o for (c3 = -n, n,
%o for (c4 = -n, n,
%o for (c5 = -n, n,
%o if ( ! polisirreducible( Pol([1,c1,c2,c3,c4,c5]) ), ct += 1 );
%o ); ); ); ); );
%o return( ct );
%o }
%o vector(7, n, a(n) )
%o \\ _Joerg Arndt_, Dec 05 2022
%Y Cf. A358398, A358399, A067274.
%K nonn,more
%O 1,1
%A _Lorenz H. Menke, Jr._, Nov 13 2022