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

1,1

Links

Table of n, a(n) for n=1..25.

Prog

(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

Crossrefs

Cf. A358398, A358400, A067274.

Sequence in context: A078965 A186169 A142119 * A231440 A142164 A201545

Adjacent sequences: A358396 A358397 A358398 * A358400 A358401 A358402

Keyword

nonn,more

Author

Lorenz H. Menke, Jr., Nov 13 2022

Status

approved