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.

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A167572 The ED3 array read by antidiagonals.

Original entry on oeis.org

1, 5, 1, 23, 11, 1, 167, 83, 17, 1, 1473, 741, 183, 23, 1, 16413, 8169, 2043, 323, 29, 1, 211479, 106107, 26529, 4409, 503, 35, 1, 3192975, 1592235, 398025, 66345, 8175, 723, 41, 1, 54010305, 27062325, 6765975, 1127655, 140865, 13677, 983, 47, 1
Offset: 1

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Author

Johannes W. Meijer, Nov 10 2009

Keywords

Comments

The coefficients in the upper right triangle of the ED3 array (m>n) were found with the a(n,m) formula while the coefficients in the lower left triangle of the ED3 array (m<=n) were found with the recurrence relation, see below. We use for the array rows the letter n (>=1) and for the array columns the letter m (>=1).
For the ED1, ED2 and ED4 arrays see A167546, A167560 and A167584.

Examples

			The ED3 array begins with:
1, 1, 1, 1, 1, 1, 1, 1, 1, 1
5, 11, 17, 23, 29, 35, 41, 47, 53, 59
23, 83, 183, 323, 503, 723, 983, 1283, 1623, 2003
167, 741, 2043, 4409, 8175, 13677, 21251, 31233, 43959, 59765
1473, 8169, 26529, 66345, 140865, 266793, 464289, 756969, 1171905, 1739625
16413, 106107, 398025, 1127655, 2678325, 5623443, 10768737, 19194495, 32297805, 51834795
		

Crossrefs

A000012, A016969, A167573, A167574 and A167575 equal the first five rows of the array.
A167576, A167577 and A167578 equal the first three columns of the array.
A167579 equals the row sums of the ED3 array read by antidiagonals.
A167580 is a triangle related to the a(n) formulas of the rows of the ED3 array.
A167583 is a triangle related to the GF(z) formulas of the rows of the ED3 array.
Cf. A014481 (the 2^(n-1)*(n-1)!*(2*n-1) factor).
Cf. A167546 (ED1 array), A167560 (ED2 array), A167584 (ED4 array).

Formula

a(n,m) = ((2*m-1)!!/ (2*m-2*n-1)!!)*int(sinh(y*(2*n-1))/(cosh(y))^(2*m),y=0..infinity) for m>n.
The (n-1)-differences of the n-th array row lead to the recurrence relation
sum((-1)^k*binomial(n-1,k)*a(n,m-k),k=0..n-1) = 2^(n-1)*(n-1)!*(2*n-1).

A167580 A triangle related to the a(n) formulas of the rows of the ED3 array A167572.

Original entry on oeis.org

1, 6, -1, 20, 0, 3, 56, 28, 98, -15, 144, 192, 1080, -48, 105, 352, 880, 7568, 2024, 6534, -945, 832, 3328, 40976, 31616, 132444, -8112, 10395, 1920, 11200, 187488, 274480, 1593960, 286900, 972162, -135135, 4352, 34816, 761600, 1784320, 13962848
Offset: 1

Views

Author

Johannes W. Meijer, Nov 10 2009

Keywords

Comments

The a(n) formulas given below correspond to the first ten rows of the ED3 array A167572.
The recurrence relations of the a(n) formulas for the left hand triangle columns, see the cross-references below, lead to the sequences A013609, A003148, A081277 and A079628.

Examples

			Row 1: a(n) = 1.
Row 2: a(n) = 6*n - 1.
Row 3: a(n) = 20*n^2 + 0*n + 3.
Row 4: a(n) = 56*n^3 + 28*n^2 + 98*n - 15.
Row 5: a(n) = 144*n^4 + 192*n^3 + 1080*n^2 - 48*n + 105.
Row 6: a(n) = 352*n^5 + 880*n^4 + 7568*n^3 + 2024*n^2 + 6534*n - 945.
Row 7: a(n) = 832*n^6 + 3328*n^5 + 40976*n^4 + 31616*n^3 + 132444*n^2 - 8112*n + 10395.
Row 8: a(n) = 1920*n^7 + 11200*n^6 + 187488*n^5 + 274480*n^4 + 1593960*n^3 + 286900*n^2 + 972162*n - 135135.
Row 9: a(n) = 4352*n^8 + 34816*n^7 + 761600*n^6 + 1784320*n^5 + 13962848*n^4 + 7874944*n^3 + 29641200*n^2 - 2080800*n + 2027025.
Row 10: a(n) = 9728*n^9 + 102144*n^8 + 2830848*n^7 + 9645312*n^6 + 98382912*n^5 + 106720416*n^4 + 522283552*n^3 + 69265488*n^2 + 255468870*n - 34459425.
		

Crossrefs

A167572 is the ED3 array.
A000012, A016969, A167573, A167574 and A167575 equal the first five rows of the ED3 array.
A014480, A167581, A167582, A168305 and A168306 equal the first five left hand triangle columns.
A001147 equals the first right hand triangle column.
A167576 equals the row sums.

Extensions

Comment and links added by Johannes W. Meijer, Nov 23 2009
Showing 1-2 of 2 results.