A358399 a(n) is the number of reducible monic quartic polynomials (x^4 + r*x^3 + s*x^2 + t*x + u) with integer coefficients bounded by naïve height n (abs(r), abs(s), abs(t), abs(u) <= n).
47, 271, 810, 1849, 3395, 5832, 8915, 13242, 18465, 25267, 32874, 43023, 53662, 66957, 81770, 99374, 117564, 140303, 163048, 190757, 219702, 252465, 285820, 326853, 366732
Offset: 1
Programs
-
PARI
{ a(n) = \\ A358399 my( ct = 0 ); for (c1 = -n, n, for (c2 = -n, n, for (c3 = -n, n, for (c4 = -n, n, if ( ! polisirreducible( Pol([1,c1,c2,c3,c4]) ), ct += 1 ); ); ); ); ); return( ct ); } vector(12, n, a(n) ) \\ Joerg Arndt, Dec 05 2022