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A292781 Triangle read by rows: T(n,k) = T(n-k,k-1) with T(0,0) = 1 and T(n,0) = -1/n * Sum_{k=1..A003056(n)} (-1)^k * (2*k+1) * (n+1-A060544(k+1)) * T(n,k). 2
1, -24, 1, 252, -24, -1472, 252, 1, 4830, -1472, -24, -6048, 4830, 252, -16744, -6048, -1472, 1, 84480, -16744, 4830, -24, -113643, 84480, -6048, 252, -115920, -113643, -16744, -1472, 534612, -115920, 84480, 4830, 1, -370944, 534612, -113643, -6048, -24 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Seiichi Manyama, Rows n = 0..481, flattened

EXAMPLE

First few rows are:

        1;

      -24,       1;

      252,     -24;

    -1472,     252,      1;

     4830,   -1472,    -24;

    -6048,    4830,    252;

   -16744,   -6048,  -1472,     1;

    84480,  -16744,   4830,   -24;

  -113643,   84480,  -6048,   252;

  -115920, -113643, -16744, -1472;

   534612, -115920,  84480,  4830, 1.

-----------------------------------------

n=5

T(5,1) = T(4,0) = 4830,  T(5,2) = T(3,1) = 252.

T(5,0) = -1/5 * Sum_{k=1..2} (-1)^k * (2*k+1) * (5+1-A060544(k+1)) * T(n,k) = -1/5 * ((-3)*(-4)*4830 + 5*(-22)*252) = -6048.

n=6

T(6,1) = T(5,0) = -6048,  T(6,2) = T(4,1) = -1472, T(6,3) = T(3,2) = 1.

T(6,0) = -1/6 * Sum_{k=1..3} (-1)^k * (2*k+1) * (6+1-A060544(k+1)) * T(n,k) = -1/6 * ((-3)*(-3)*(-6048) + 5*(-21)*(-1472) - 7*(-48)*1) = -16744.

PROG

(Ruby)

def A292781(n)

  ary = [[1]]

  (1..n).each{|i|

    m = ((Math.sqrt(1 + 8 * i) - 1) / 2).to_i

    a = (1..m).map{|j| ary[i - j][j - 1]}

    ary << [-(1..m).inject(0){|s, j| s + (-1) ** (j % 2) * (2 * j + 1) * (i - 9 * j * (j + 1) / 2) * a[j - 1]} / i] + a

  }

  ary.flatten

end

p A292781(20)

CROSSREFS

All columns are A000594.

Cf. A003056, A060544.

Sequence in context: A040599 A076721 A232988 * A090215 A318105 A040570

Adjacent sequences:  A292778 A292779 A292780 * A292782 A292783 A292784

KEYWORD

sign,tabf

AUTHOR

Seiichi Manyama, Sep 23 2017

STATUS

approved

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Last modified February 19 18:22 EST 2019. Contains 320327 sequences. (Running on oeis4.)