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.

Showing 1-10 of 13 results. Next

A137505 Inverse binomial transform of A007910.

Original entry on oeis.org

1, 1, 0, 2, 0, 0, 4, -4, 4, 4, -12, 20, -12, -12, 52, -76, 52, 52, -204, 308, -204, -204, 820, -1228, 820, 820, -3276, 4916, -3276, -3276, 13108, -19660, 13108, 13108, -52428, 78644, -52428, -52428, 209716, -314572, 209716, 209716, -838860, 1258292, -838860, -838860, 3355444, -5033164, 3355444
Offset: 0

Views

Author

Paul Curtz, Apr 23 2008

Keywords

Programs

  • Mathematica
    LinearRecurrence[{-1,0,2},{1,1,0},50] (* Harvey P. Dale, Sep 17 2012 *)

Formula

Recurrence: a(n) = -a(n-1) + 2a(n-3), starting 1,1,0.
O.g.f.: (1+x)^2/((1-x)(1+2x+2x^2)). - R. J. Mathar, Jun 12 2008
a(4n) = a(4n+1) = (-1)^n*A109499(n). - Paul Curtz, Nov 01 2009
a(n) = (1/5) * (A137429(n-1) + 4) = A077973(n-2) + 2*A077973(n-1) + A077973(n). - Ralf Stephan, Aug 18 2013

Extensions

More terms from R. J. Mathar, Jun 12 2008

A137500 Binomial transform of b(n) = (0, 0, A007910).

Original entry on oeis.org

0, 0, 1, 5, 17, 51, 149, 439, 1309, 3927, 11797, 35423, 106301, 318903, 956645, 2869807, 8609293, 25827879, 77483893, 232452191, 697357085, 2092071255, 6276212741, 18828636175, 56485906477, 169457719431, 508373162389, 1525119495359, 4575358494269, 13726075482807
Offset: 0

Views

Author

Paul Curtz, Apr 27 2008

Keywords

Comments

b(n) is binomial transform of (0, 0, A077973).

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{5,-8,6},{0,0,1},40] (* Harvey P. Dale, Sep 27 2020 *)
  • PARI
    concat([0,0], Vec(1/((1 - 3*x)*(1 - 2*x + 2*x^2)) + O(x^40))) \\ Andrew Howroyd, Jan 03 2020

Formula

a(n) = 3*a(n-1) + A009545(n-1) for n > 0.
From Andrew Howroyd, Jan 03 2020: (Start)
a(n) = Sum_{k=0..n-2} binomial(n, k+2)*A007910(k).
a(n) = 5*a(n-1) - 8*a(n-2) + 6*a(n-3) for n >= 3.
G.f.: x*2/((1 - 3*x)*(1 - 2*x + 2*x^2)). (End)

Extensions

Terms a(11) and beyond from Andrew Howroyd, Jan 03 2020

A381255 Positive integers not of the form round(2^(k+2)/5). Complement of A007910.

Original entry on oeis.org

4, 5, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74
Offset: 1

Views

Author

Chai Wah Wu, Apr 21 2025

Keywords

Crossrefs

Cf. A007910.

Programs

  • Python
    def A381255(n): return (m:=n-2+(k:=(5*n+3).bit_length()))+(m>=((1<
    				

Formula

a(n) = m+1 if m>=floor((2^k+2)/5) otherwise a(n) = m where k = floor(log_2(5*n+3))+1 and m = n-2+k.

A113405 Expansion of x^3/(1 - 2*x + x^3 - 2*x^4) = x^3/( (1-2*x)*(1+x)*(1-x+x^2) ).

Original entry on oeis.org

0, 0, 0, 1, 2, 4, 7, 14, 28, 57, 114, 228, 455, 910, 1820, 3641, 7282, 14564, 29127, 58254, 116508, 233017, 466034, 932068, 1864135, 3728270, 7456540, 14913081, 29826162, 59652324, 119304647, 238609294, 477218588, 954437177, 1908874354, 3817748708
Offset: 0

Views

Author

Paul Barry, Oct 28 2005

Keywords

Comments

A transform of the Jacobsthal numbers. A059633 is the equivalent transform of the Fibonacci numbers.
Paul Curtz, Aug 05 2007, observes that the inverse binomial transform of 0,0,0,1,2,4,7,14,28,57,114,228,455,910,1820,... gives the same sequence up to signs. That is, the extended sequence is an eigensequence for the inverse binomial transform (an autosequence).
The round() function enables the closed (non-recurrence) formula to take a very simple form: see Formula section. This can be generalized without loss of simplicity to a(n) = round(b^n/c), where b and c are very small, incommensurate integers (c may also be an integer fraction). Particular choices of small integers for b and c produce a number of well-known sequences which are usually defined by a recurrence - see Cross Reference. - Ross Drewe, Sep 03 2009

Crossrefs

From Ross Drewe, Sep 03 2009: (Start)
Other sequences a(n) = round(b^n / c), where b and c are very small integers:
A001045 b = 2; c = 3
A007910 b = 2; c = 5
A016029 b = 2; c = 5/3
A077947 b = 2; c = 7
abs(A078043) b = 2; c = 7/3
A007051 b = 3; c = 2
A015518 b = 3; c = 4
A034478 b = 5; c = 2
A003463 b = 5; c = 4
A015531 b = 5; c = 6
(End)

Programs

  • Magma
    [Round(2^n/9): n in [0..40]]; // Vincenzo Librandi, Aug 11 2011
    
  • Maple
    A010892 := proc(n) op((n mod 6)+1,[1,1,0,-1,-1,0]) ; end proc:
    A113405 := proc(n) (2^n-(-1)^n)/9 -A010892(n-1)/3; end proc: # R. J. Mathar, Dec 17 2010
  • Mathematica
    CoefficientList[Series[x^3/(1-2x+x^3-2x^4),{x,0,40}],x] (* or *) LinearRecurrence[{2,0,-1,2},{0,0,0,1},40] (* Harvey P. Dale, Apr 30 2011 *)
  • PARI
    a(n)=2^n\/9 \\ Charles R Greathouse IV, Jun 05 2011
    
  • Python
    def A113405(n): return ((1<Chai Wah Wu, Apr 17 2025

Formula

a(n) = 2a(n-1) - a(n-3) + 2a(n-4).
a(n) = Sum_{k=0..floor(n/2)} binomial(n-k,k)*A001045(k).
a(n) = Sum_{k=0..n} binomial((n+k)/2,k)*A001045((n-k)/2)*(1+(-1)^(n-k))/2.
a(3n) = A015565(n), a(3n+1) = 2*A015565(n), a(3n+2) = 4*A015565(n). - Paul Curtz, Nov 30 2007
From Paul Curtz, Dec 16 2007: (Start)
a(n+1) - 2a(n) = A131531(n).
a(n) + a(n+3) = 2^n. (End)
a(n) = round(2^n/9). - Ross Drewe, Sep 03 2009
9*a(n) = 2^n + (-1)^n - 3*A010892(n). - R. J. Mathar, Mar 24 2018

Extensions

Edited by N. J. A. Sloane, Dec 13 2007

A077854 Expansion of 1/((1-x)*(1-2*x)*(1+x^2)).

Original entry on oeis.org

1, 3, 6, 12, 25, 51, 102, 204, 409, 819, 1638, 3276, 6553, 13107, 26214, 52428, 104857, 209715, 419430, 838860, 1677721, 3355443, 6710886, 13421772, 26843545, 53687091, 107374182, 214748364, 429496729, 858993459, 1717986918, 3435973836, 6871947673
Offset: 0

Views

Author

N. J. A. Sloane, Nov 17 2002

Keywords

Comments

Partial sums of A007910. - Mircea Merca, Dec 27 2010
This is the decimal representation of the middle column of "Rule 54" elementary cellular automaton. - Karl V. Keller, Jr., Sep 26 2021
This same sequence (except that the offset is changed to 4) is 2^n with the final digit chopped off. - J. Lowell, May 11 2022

Examples

			The sequence in hexadecimal shows the pattern
1, 3, 6, c,
19, 33, 66, cc,
199, 333, 666, ccc,
1999, 3333, 6666, cccc,
19999, 33333, 66666, ccccc,
199999, 333333, 666666, cccccc,
1999999, 3333333, 6666666, ccccccc,
19999999, 33333333, 66666666, cccccccc,
... - _Armands Strazds_, Oct 09 2014
		

Crossrefs

Equals A007909(n+3) - [n congruent 2, 3 mod 4].
Cf. A130306, A043291 (subsequence); A000975, A007910, A133872, A259661 (binary).

Programs

  • Haskell
    import Data.Bits (xor)
    a077854 n = a077854_list !! n
    a077854_list = scanl1 xor $ tail a000975_list :: [Integer]
    -- Reinhard Zumkeller, Jan 04 2013
    
  • Magma
    [Round((2^(n+4)-5)/10): n in [0..40]]; // Vincenzo Librandi, Jun 25 2011
    
  • Maple
    a := proc(n) option remember; if n=0 then RETURN(1); fi; if n=1 then RETURN(3); fi; if n=2 then RETURN(6); fi; if n=3 then RETURN(12); fi; 3*a(n-1)-3*a(n-2)+3*a(n-3)-2*a(n-4); end;
    seq(iquo(2^n,5),n=3..35); # Zerinvary Lajos, Apr 20 2008
  • Mathematica
    CoefficientList[Series[1/((1 - x) (1 - 2 x) (1 + x^2)), {x, 0, 32}], x] (* Michael De Vlieger, Mar 29 2016 *)
    LinearRecurrence[{3,-3,3,-2},{1,3,6,12},40] (* Harvey P. Dale, Feb 06 2019 *)
  • PARI
    a(n)=(16<Charles R Greathouse IV, Sep 23 2012
    
  • PARI
    Vec(1/(1-3*x+3*x^2-3*x^3+2*x^4)+O(x^99)) \\ Derek Orr, Oct 26 2014
    
  • Python
    print([2**(n+3)//5 for n in range(50)]) # Karl V. Keller, Jr., Sep 26 2021

Formula

a(n) = 3*a(n-1) - 3*a(n-2) + 3*a(n-3) - 2*a(n-4), with initial values a(0) = 1, a(1) = 3, a(2) = 6, a(3) = 12.
a(n) = (1/10)*(2^(n+4) + (-1)^floor(n/2) - 2*(-1)^floor((n+1)/2) - 5).
Row sums of A130306. - Gary W. Adamson, May 20 2007
a(n) = floor(2^(n+3)/5). - Gary Detlefs, Sep 06 2010
a(n) = round((2^(n+4)-5)/10) = floor((2^(n+3)-1)/5) = ceiling((2^(n+3)-4)/5) = round((2^(n+3)-2)/5); a(n) = a(n-4) + 3*2^(n-1), n > 3. - Mircea Merca, Dec 27 2010
a(n) = 2^(n+1) - 1 - a(n-2); a(n) = a(n-1)/2 for n == 2, 3 (mod 4); a(n) = (a(n-1)-1)/2 for n == 0, 1 (mod 4). - Arie Bos, Apr 06 2013
a(n) = floor(A000975(n+2)*3/5). - Armands Strazds, Oct 18 2014
a(n) = Sum_{k=1..n+3} floor(1 + sin(k*Pi/2 + 3*Pi/4))*2^(n-k+3). - Andres Cicuttin, Mar 28 2016
a(n) = (-15 + 3*2^(3+n) + 2^(1 + n - 4*floor((1+n)/4)) + 2^(2 + n - 4*floor((2+n)/4)))/15. - Andres Cicuttin, Mar 28 2016
a(n) = (16*2^n+(-1)^((2*n-1+(-1)^n)/4)-2*(-1)^((2*n+1-(-1)^n)/4)-5)/10. - Wesley Ivan Hurt, Apr 01 2016

A007909 Expansion of (1-x)/(1-2*x+x^2-2*x^3).

Original entry on oeis.org

1, 1, 1, 3, 7, 13, 25, 51, 103, 205, 409, 819, 1639, 3277, 6553, 13107, 26215, 52429, 104857, 209715, 419431, 838861, 1677721, 3355443, 6710887, 13421773, 26843545, 53687091, 107374183, 214748365, 429496729, 858993459, 1717986919, 3435973837, 6871947673
Offset: 0

Views

Author

Mogens Esrom Larsen (mel(AT)math.ku.dk)

Keywords

Comments

Equals INVERT transform of (1, 0, 2, 2, 2, ...). - Gary W. Adamson, Apr 28 2009
a(n) is the number of compositions (ordered partitions) of n into parts 1 (one kind), and parts >= 3 of three kinds (no parts 2). - Joerg Arndt, Apr 22 2025

References

  • Kenneth Edwards, Michael A. Allen, A new combinatorial interpretation of the Fibonacci numbers squared, Part II, Fib. Q., 58:2 (2020), 169-177.
  • M. E. Larsen, Summa Summarum, A. K. Peters, Wellesley, MA, 2007; see p. 38.

Crossrefs

Programs

  • Magma
    I:=[1, 1, 1]; [n le 3 select I[n] else 2*Self(n-1)-Self(n-2)+2*Self(n-3): n in [1..40]]; // Vincenzo Librandi, Jun 17 2012
    
  • Maple
    U:=n->(1/5)*(2^(n+1)+3*cos(n*Pi/2)+sin(n*Pi/2)); [seq(U(n),n=0..50)];
  • Mathematica
    CoefficientList[Series[(1-x)/(1-2*x+x^2-2*x^3),{x,0,40}],x] (* Vincenzo Librandi, Jun 17 2012 *)
    LinearRecurrence[{2,-1,2},{1,1,1},40] (* Harvey P. Dale, Jul 26 2016 *)
  • PARI
    a(n)=2^(n+1)\5+(n%4<2) \\ M. F. Hasler, Feb 22 2018
    
  • Python
    def A007909(n): return (2<Chai Wah Wu, Apr 22 2025

Formula

G.f.: (1-x)/(1-2*x+x^2-2*x^3).
a(n) = (1/5)*(2^(n+1)+3*cos(n*Pi/2)+sin(n*Pi/2)).
a(n) = Sum_{k=0..floor((n-1)/3)} binomial(n-k-1, 2*k)*2^k. - Paul Barry, Sep 16 2004
a(n) = (1/5)*(2^(n+1) + (-1)^[(n+1)/2] + 2*(-1)^[n/2]). - Ralf Stephan, Jun 09 2005
a(n) = 2*a(n-1)-a(n-2)+2*a(n-3). Sequence is identical to its half second differences from the second term; a(n)+a(n+2)=2^(n+1). - Paul Curtz, Dec 17 2007
a(n+1) = (2^n)*Sum_{k=1..n} (-1)^floor(k/2)/2^k. - Yalcin Aktar, Jul 20 2008

Extensions

Offset corrected by M. F. Hasler, Feb 22 2018

A299960 a(n) = (4^(2*n+1) + 1) / 5.

Original entry on oeis.org

1, 13, 205, 3277, 52429, 838861, 13421773, 214748365, 3435973837, 54975581389, 879609302221, 14073748835533, 225179981368525, 3602879701896397, 57646075230342349, 922337203685477581, 14757395258967641293, 236118324143482260685, 3777893186295716170957
Offset: 0

Views

Author

M. F. Hasler, Feb 22 2018

Keywords

Comments

It is easily seen that 4^(2n+1)+1 is divisible by 5 for all n, since 4 = -1 (mod 5). For even powers this does not hold.
The aerated sequence 1, 0, 13, 0, 205, 0, 3277, ... is a linear divisibility sequence of order 4. It is the case P1 = 0, P2 = -5^2, Q = 4 of the 3-parameter family of 4th-order linear divisibility sequences found by Williams and Guy. Cf. A007583, A095372 and A100706. - Peter Bala, Aug 28 2019
Let G be a sequence satisfying G(i) = 2*G(i-1) + G(i-2) - 2*G(i-3) for arbitrary integers i and without regard to the initial values of G. Then a(n) = (G(i)*2^(4*n+2) + G(i+8*n+4))/(5*G(i+4*n+2)) as long as G(i+4*n+2) != 0. - Klaus Purath, Feb 02 2021
Ch. Gerbr asks (personal comm.) whether we can prove that 13 is the only prime in this sequence. We can prove divisibility conditions for many residue classes of the index n (cf. formulas), but have not yet found a complete covering set. - M. F. Hasler, Jan 07 2025

Examples

			For n = 0, a(0) = (4^1+1)/5 = 5/5 = 1.
For n = 1, a(1) = (4^3+1)/5 = 65/5 = 13.
		

Crossrefs

Cf. A299959 for the smallest prime factor.

Programs

Formula

a(n) = A052539(2*n+1)/5 = A015521(2*n+1) = A014985(2*n+1) = A007910(4*n+1) = A007909(4*n+1) = A207262(n+1)/5.
O.g.f.: (1 - 4*x)/(1 - 17*x + 16*x^2). - Peter Bala, Aug 28 2019
a(n) = 17*a(n-1) - 16*a(n-2). - Wesley Ivan Hurt, Oct 02 2020
From Klaus Purath, Feb 02 2021: (Start)
a(n) = (2^(4*n+2)+1)/5.
a(n) = (A061654(n) + A001025(n))/2.
a(n) = A091881(n+1) + 7*A131865(n-1) for n > 0.
(End)
E.g.f.: (exp(x) + 4*exp(16*x))/5. - Stefano Spezia, Feb 02 2021
We have d | a(n) for all n in R, for the following pairs (d, R) of divisors d and residue classes R: (13, 1 + 3Z), (5, 2 + 5Z), (29, 3 + 7Z), (397, 5 + 11Z),
(53, 6 + 13Z), (137, 8 + 17Z), (229, 9 + 19Z), (277, 11 + 23Z),
(107367629, 14 + 29Z), (5581, 15 + 31Z), (149, 18 + 27Z), (10169, 20 + 41Z),
(173, 21 + 43Z), (3761, 23 + 47Z), (15358129, 26 + 53Z), (1181, 29 + 59Z),
(733, 30 + 61Z), (269, 33 + 67Z), (569, 35 + 71Z),(293, 36 + 73Z), (317, 39 + 79Z),
(997, 41 + 83Z), (1069, 44 + 89Z), (389, 48 + 97Z), (809, 50 + 101Z),
(41201, 51 + 103Z), (857, 53 + 107Z), (5669, 54 + 109Z), (58309, 56 + 113Z),
(509, 63 + 127Z), (269665073, 65 + 131Z), (189061, 68 + 137Z), (557, 69 + 139Z),
(1789, 74 + 149Z), (653, 81 + 163Z), (9413, 90 + 181Z), (3821, 95 + 191Z),
(773, 96 + 193Z), (4729, 98 + 197Z), (797, 99 + 199Z), ... - M. F. Hasler, Jan 07 2025

A054106 Alternating sums of vertically aligned numbers in Pascal's triangle: T(n,k) = C(n,k) - C(n-2,k-1) + C(n-4,k-2) - ... +- C(n-2[n/2],m).

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 3, 5, 3, 1, 1, 4, 8, 8, 4, 1, 1, 5, 12, 15, 12, 5, 1, 1, 6, 17, 27, 27, 17, 6, 1, 1, 7, 23, 44, 55, 44, 23, 7, 1, 1, 8, 30, 67, 99, 99, 67, 30, 8, 1, 1, 9, 38, 97, 166, 197, 166, 97, 38, 9, 1, 1, 10, 47, 135, 263, 363, 363
Offset: 0

Views

Author

Keywords

Examples

			Rows: {1}; {1,1}; {1,1,1}; {1,2,2,1}; {1,3,5,3,1} ...
		

Crossrefs

For (nonalternating) vertically aligned sums, see A013580.
Row sums of this array: A007910.

Formula

G.f.: 1/(1-(1+y)*x)/(1+y*x^2). - Vladeta Jovovic, Oct 12 2003

A100088 Expansion of (1-x^2)/((1-2*x)*(1+x^2)).

Original entry on oeis.org

1, 2, 2, 4, 10, 20, 38, 76, 154, 308, 614, 1228, 2458, 4916, 9830, 19660, 39322, 78644, 157286, 314572, 629146, 1258292, 2516582, 5033164, 10066330, 20132660, 40265318, 80530636, 161061274, 322122548, 644245094, 1288490188, 2576980378
Offset: 0

Views

Author

Paul Barry, Nov 03 2004

Keywords

Comments

A Chebyshev transform of A100087, under the mapping A(x) -> ((1-x^2)/(1+x^2)) * A(x/(1+x^2)).
A176742(n+2) = A084099(n+2) = period 4:repeat 0, -2, 0, 2.

Crossrefs

Programs

  • Magma
    [n le 3 select Floor((n+2)/2) else 2*Self(n-1) - Self(n-2) +2*Self(n-3): n in [1..41]]; // G. C. Greubel, Jul 08 2022
    
  • Mathematica
    CoefficientList[Series[(1-x^2)/((1-2x)(1+x^2)),{x,0,40}],x] (* or *) LinearRecurrence[{2,-1,2},{1,2,2},40] (* Harvey P. Dale, May 12 2011 *)
  • Python
    def A100088(n): return ((4<Chai Wah Wu, Apr 22 2025
  • SageMath
    def b(n): return (2/5)*(3*2^(2*n-1) + (-1)^n) # b=A122117
    def A100088(n): return b(n/2) if (n%2==0) else 2*b((n-1)/2)
    [A100088(n) for n in (0..60)]  # G. C. Greubel, Jul 08 2022
    

Formula

a(n) = (3*2^n + 2*cos(Pi*n/2) + 4*sin(Pi*n/2))/5.
a(n) = n*Sum_{k=0..floor(n/2)} binomial(n-k, k)*(-1)^k*A100087(n-2*k)/(n-k).
a(n) = 2*a(n-1) + period 4:repeat 0, -2, 0, 2, with a(0) = 1.
a(n) = A007910(n+1) - A007910(n-1).
a(n) = 2*a(n-1) - a(n-2) + 2*a(n-3).
a(n) = (1/5)*(3*2^n + i^n*(1+(-1)^n) - 2*i^(n+1)*(1-(-1)^n)). - G. C. Greubel, Jul 08 2022
a(n) = A122117(n/2) if (n mod 2 = 0) otherwise 2*A122117((n-1)/2). - G. C. Greubel, Jul 21 2022

A118404 Triangle T, read by rows, where all columns of T are different and yet all columns of the matrix square T^2 (A118407) are equal; also equals the matrix inverse of triangle A118400.

Original entry on oeis.org

1, 1, -1, -1, 0, 1, -1, 1, -1, -1, 1, 0, 0, 2, 1, 1, -1, 0, -2, -3, -1, -1, 0, 1, 2, 5, 4, 1, -1, 1, -1, -3, -7, -9, -5, -1, 1, 0, 0, 4, 10, 16, 14, 6, 1, 1, -1, 0, -4, -14, -26, -30, -20, -7, -1, -1, 0, 1, 4, 18, 40, 56, 50, 27, 8, 1, -1, 1, -1, -5, -22, -58, -96, -106, -77, -35, -9, -1, 1, 0, 0, 6, 27, 80, 154, 202, 183, 112, 44, 10, 1, 1, -1, 0, -6, -33, -107, -234, -356, -385, -295, -156, -54, -11, -1, -1, 0, 1, 6, 39, 140, 341, 590, 741, 680, 451, 210, 65, 12, 1, -1, 1, -1, -7, -45, -179, -481, -931, -1331, -1421, -1131, -661, -275, -77, -13, -1, 1, 0, 0, 8, 52, 224, 660, 1412, 2262, 2752, 2552, 1792, 936, 352, 90, 14, 1
Offset: 0

Views

Author

Paul D. Hanna, Apr 27 2006

Keywords

Comments

Appears to coincide with triangle (5.2) in Lee-Oh (2016), although there is no obvious connection! - N. J. A. Sloane, Dec 07 2016

Examples

			Triangle begins:
1;
1,-1;
-1, 0, 1;
-1, 1,-1,-1;
1, 0, 0, 2, 1;
1,-1, 0,-2,-3,-1;
-1, 0, 1, 2, 5, 4, 1;
-1, 1,-1,-3,-7,-9,-5,-1;
1, 0, 0, 4, 10, 16, 14, 6, 1;
1,-1, 0,-4,-14,-26,-30,-20,-7,-1;
-1, 0, 1, 4, 18, 40, 56, 50, 27, 8, 1;
-1, 1,-1,-5,-22,-58,-96,-106,-77,-35,-9,-1;
1, 0, 0, 6, 27, 80, 154, 202, 183, 112, 44, 10, 1;
1, -1, 0, -6, -33, -107, -234, -356, -385, -295, -156, -54, -11, -1;
-1, 0, 1, 6, 39, 140, 341, 590, 741, 680, 451, 210, 65, 12, 1;
-1, 1, -1, -7, -45, -179, -481, -931, -1331, -1421, -1131, -661, -275, -77, -13, -1;
1, 0, 0, 8, 52, 224, 660, 1412, 2262, 2752, 2552, 1792, 936, 352, 90, 14, 1;
1, -1, 0, -8, -60, -276, -884, -2072, -3674, -5014, -5304, -4344, -2728, -1288, -442, -104, -15, -1;
-1, 0, 1, 8, 68, 336, 1160, 2956, 5746, 8688, 10318, 9648, 7072, 4016, 1730, 546, 119, 16, 1; ...
The matrix square is A118407:
1;
0, 1;
-2, 0, 1;
2,-2, 0, 1;
0, 2,-2, 0, 1;
-2, 0, 2,-2, 0, 1;
4,-2, 0, 2,-2, 0, 1;
-6, 4,-2, 0, 2,-2, 0, 1;
4,-6, 4,-2, 0, 2,-2, 0, 1;
6, 4,-6, 4,-2, 0, 2,-2, 0, 1; ...
in which all columns are equal.
		

Crossrefs

Cf. A118405 (row sums), A118406 (unsigned row sums), A118407 (matrix square), A118400 (matrix inverse).
Columns or diagonals (modulo offsets): A219977, A011848, A212342, A007598, A005581, A007910.

Programs

  • Mathematica
    T[n_, k_] := SeriesCoefficient[(-1)^k/((1+x^2)(1+x)^(k-1)), {x, 0, n-k}];
    Table[T[n, k], {n, 0, 16}, {k, 0, n}] // Flatten (* Jean-François Alcover, Jul 26 2018 *)
  • PARI
    {T(n,k)=polcoeff(polcoeff((1+x)^2/(1+x^2)/(1+x+x*y +x*O(x^n)),n,x)+y*O(y^k),k,y)}
    for(n=0, 16, for(k=0, n, print1(T(n, k), ", ")); print(""))

Formula

G.f.: A(x,y) = (1+x)^2 / ( (1+x^2) * (1+x + x*y) ).
G.f. of column k: (-1)^k / ( (1+x^2) * (1+x)^(k-1) ) for k>=0.
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