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A102728 Array read by antidiagonals: T(n, k) = ((n+1)^k-(n-1)^k)/2. 2
0, 0, 1, 0, 1, 0, 0, 1, 2, 1, 0, 1, 4, 4, 0, 0, 1, 6, 13, 8, 1, 0, 1, 8, 28, 40, 16, 0, 0, 1, 10, 49, 120, 121, 32, 1, 0, 1, 12, 76, 272, 496, 364, 64, 0, 0, 1, 14, 109, 520, 1441, 2016, 1093, 128, 1, 0, 1, 16, 148, 888, 3376, 7448, 8128, 3280, 256, 0, 0, 1, 18, 193, 1400, 6841 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,9

COMMENTS

Consider a 2 X 2 matrix M = [N, 1] / [1, N]. The n-th row of the array contains the values of the non diagonal elements of M^k, k=0,1,.... (Corresponding diagonal entry = non diagonal entry + (N-1)^k.) Table:

N: row sequence G.f. cross references.

0: (1^n-(-1)^n)/2 x/((1+1x)(1-1x)) A000035

1: (2^n-0^n)/2 x/(1-2x) A000079

2: (3^n-1^n)/2 x/((1-1x)(1-3x)) A003462

3: (4^n-2^n)/2 x/((1-2x)(1-4x)) A006516

4: (7^n-3^n)/2 x/((1-3x)(1-5x)) A005059

5: (6^n-4^n)/2 x/((1-4x)(1-6x)) A016149

6: (7^n-5^n)/2 x/((1-5x)(1-7x)) A016161 A081200

7: (8^n-6^n)/2 x/((1-6x)(1-8x)) A016170 A081201

8: (9^n-7^n)/2 x/((1-7x)(1-9x)) A016178 A081202

9: (10^n-8^n)/2 x/((1-8x)(1-10x)) A016186 A081203

10: (11^n-9^n)/2 x/((1-9x)(1-11x)) A016190

11: (12^n-10^n)/2 x/((1-10x)(1-12x)) A016196

...

Characteristic polynomial x^2-2nx+(n^2-1) has roots n+-1, so if r(n) denotes a row sequence, r(n+1)/r(n) converges to n+1.

Columns follow polynomials with certain binomial coefficients:

column: polynomial

0: 0

1: 1

2: 2n

3: 3n^2+ 1 (see A056107)

4: 4n^3+ 4n (= 8*A006003(n))

5: 5n^4+ 10n^2+ 1

6: 6n^5+ 20n^3+ 6n

7: 7n^6+ 35n^4+ 21n^2+ 1

8; 8n^7+ 56n^5+ 56n^3+ 8n

9: 9n^8+ 84n^6+126n^4+ 36n^2+ 1

10: 10n^9+ 120n^7+252n^5+120n^3+ 10n

11: 11n^10+165n^8+462n^6+330n^4+ 55n^2+ 1

LINKS

Table of n, a(n) for n=0..71.

EXAMPLE

Array begins:

0,1,0,1,0,1...

0,1,2,4,8,16...

0,1,4,13,40,121...

0,1,6,28,120,496...

0,1,8,49,272,1441...

...

PROG

(PARI) MM(n, N)=local(M); M=matrix(n, n); for(i=1, n, for(j=1, n, if(i==j, M[i, j]=N, M[i, j]=1))); M for(k=0, 12, for(i=0, k, print1((MM(2, k-i)^i)[1, 2], ", "))) T(n, k) = ((n+1)^k-(n-1)^k)/2 for(k=0, 10, for(i=0, 10, print1(T(k, i), ", ")); print()) for(k=0, 10, for(i=0, 10, print1(((k+1)^i-(k-1)^i)/2, ", ")); print()) for(k=0, 10, for(i=0, 10, print1(polcoeff(x/((1-(k-1)*x)*(1-(k+1)*x)), i), ", ")); print())

CROSSREFS

Sequence in context: A034373 A238889 A253628 * A262495 A165519 A266972

Adjacent sequences:  A102725 A102726 A102727 * A102729 A102730 A102731

KEYWORD

nonn,tabl

AUTHOR

Lambert Klasen (lambert.klasen(AT)gmx.net) and Gary W. Adamson, Feb 07 2005

STATUS

approved

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Last modified November 21 16:08 EST 2017. Contains 295003 sequences.