cp's OEIS Frontend

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.

A238146 Triangle read by rows: T(n,k) is coefficient of x^(n-k) in consecutive prime rooted polynomial of degree n, P(x) = Product_{k=1..n} (x-p(k)) = 1*x^n + T(n,1)*x^(n-1)+ ... + T(n,k-1)*x + T(n,k), for 1 <= k <= n.

Original entry on oeis.org

-2, -5, 6, -10, 31, -30, -17, 101, -247, 210, -28, 288, -1358, 2927, -2310, -41, 652, -5102, 20581, -40361, 30030, -58, 1349, -16186, 107315, -390238, 716167, -510510, -77, 2451, -41817, 414849, -2429223, 8130689, -14117683, 9699690
Offset: 1

Views

Author

Fedor Igumnov, Feb 18 2014

Keywords

Comments

The coefficient of first polynomial term with highest degree is always 1.
Each number in triangle is the sum of radicals of integers.
The absolute value of the entry in the k-th column is the k-th elementary symmetric function of the first n+(k-1) primes.

Examples

			Triangle begins:
================================================
\k |    1     2     3     4     5     6     7
n\ |
================================================
1  |  -2;
2  |  -5,   6;
3  |  -10,  31,   -30;
4  |  -17, 101,  -247,  210;
5  |  -28, 288, -1358,  2927,  -2310;
6  |  -41, 652, -5102, 20581, -40361, 30030;
7  |  -58,1349,-16186,107315,-390238,716167,-510510;
So equation x^7 -58*x^6 + 1349*x^5 -16186*x^4 + 107315*x^3 -390238*x^2+ 716167*x -510510 = 0 has 7 consecutive prime roots: 2,3,5,7,11,13,17
		

Crossrefs

Cf. A007504 (abs of column 1) A002110(abs of right border). Also:
A024447 is the abs of column 2;
A024448 is the abs of column 3;
A024449 is the abs of column 4;
A006939 is the determinant of triangle matrix, considering T(n,k) k>n = 0;
A007947 = radicals of integers.

Programs

  • Maple
    T:= n-> (p-> seq(coeff(p, x, n-i), i=1..n))(mul(x-ithprime(i), i=1..n)):
    seq(T(n), n=1..10);  # Alois P. Heinz, Aug 18 2019
  • Mathematica
    a = 1
    For [i = 1, i < 10, i++,
    a *= (x - Prime[i]);
    Print[Drop[Reverse[CoefficientList[Expand[a], x]], 1]]
    ]

Extensions

Name edited by Alois P. Heinz, Aug 18 2019