A001469 -id:A001469 - cp's OEIS frontend

A064624 Generalization of the Genocchi numbers given by the Gandhi polynomials A(n+1,r) = r^3 A(n, r + 1) - (r - 1)^3 A(n, r); A(1,r) = r^3 - (r-1)^3.

1, 1, 7, 145, 6631, 566641, 81184327, 18070338385, 5905039303591, 2711929990866481, 1690633724369840647, 1390752644563701636625, 1474612871875198657851751, 1975728790062794178772769521

Offset: 0

Mike Domaratzki (mdomaratzki(AT)alumni.uwaterloo.ca), Sep 28 2001

			O.g.f.: A(x) = 1 + x + 7*x^2 + 145*x^3 + 6631*x^4 + 566641*x^5 +...
where A(x) = 1 + x/(1+x) + 2!^3*x^2/((1+x)*(1+8*x)) + 3!^3*x^3/((1+x)*(1+8*x)*(1+27*x)) + 4!^3*x^4/((1+x)*(1+8*x)*(1+27*x)*(1+64*x)) +... [From Paul D. Hanna, Jul 21 2011]

M. Domaratzki, A Generalization of the Genocchi Numbers with Applications to Enumeration of Finite Automata, Technical Report 2001-449, Department of Computing and Information Science, Queen's University of Kingston (Kingston, Canada).

M. Domaratzki, A Generalization of the Genocchi Numbers with Applications to ...
Michael Domaratzki, Combinatorial Interpretations of a Generalization of the Genocchi Numbers, Journal of Integer Sequences, Vol. 7 (2004), Article 04.3.6.

Cf. A001469, A064625.

a[n_ /; n >= 0, r_ /; r >= 0] := a[n, r] = r^3*a[n-1, r+1] - (r-1)^3*a[n-1, r]; a[1, r_ /; r >= 0] := r^3-(r-1)^3; a[, ] = 1; a[n_] := a[n-1, 1]; Table[a[n], {n, 0, 13}] (* Jean-François Alcover, May 23 2013 *)

{a(n)=polcoeff(sum(m=0,n,m!^3*x^m/prod(k=1,m,1+k^3*x+x*O(x^n))),n)}

a(n) = A(n-1, 1) for the above Gandhi polynomials.

O.g.f.: Sum_{n>=0} n!^3 * x^n / Product_{k=1..n} (1 + k^3*x). [From Paul D. Hanna, Jul 21 2011]

A064625 Generalization of the Genocchi numbers. Generated by the Gandhi polynomials A(n+1,r) = r^4 A(n,r+1) - (r-1)^4 A(n,r); A(1,r) = r^4 - (r-1)^4.

Original entry on oeis.org

1, 1, 15, 1025, 209135, 100482849, 97657699279, 172687606607425, 513828770061202095, 2422699282016359575905, 17259669919850500726265231, 178741720937382151333667162241, 2605965447000176066894638515610735

Offset: 0

Mike Domaratzki (mdomaratzki(AT)alumni.uwaterloo.ca), Sep 28 2001

			O.g.f.: A(x) = 1 + x + 15*x^2 + 1025*x^3 + 209135*x^4 + 100482849*x^5 +...
where A(x) = 1 + x/(1+x) + 2!^4*x^2/((1+x)*(1+16*x)) + 3!^4*x^3/((1+x)*(1+16*x)*(1+81*x)) + 4!^4*x^4/((1+x)*(1+16*x)*(1+81*x)*(1+256*x)) +... [From Paul D. Hanna, Jul 21 2011]

M. Domaratzki, A Generalization of the Genocchi Numbers with Applications to Enumeration of Finite Automata. Technical Report 2001-449, Department of Computing and Information Science, Queen's University at Kingston (Kingston, Canada).

M. Domaratzki, A Generalization of the Genocchi Numbers with Applications to ...
Michael Domaratzki, Combinatorial Interpretations of a Generalization of the Genocchi Numbers, Journal of Integer Sequences, Vol. 7 (2004), Article 04.3.6.

Cf. A001469, A064624.

a[n_ /; n >= 0, r_ /; r >= 0] := a[n, r] = r^4*a[n-1, r+1]-(r-1)^4*a[n-1, r]; a[1, r_ /; r >= 0] := r^4-(r-1)^4; a[, ] = 1; a[n_] := a[n-1, 1]; Table[a[n], {n, 0, 12}] (* Jean-François Alcover, May 23 2013 *)

{a(n)=polcoeff(sum(m=0,n,m!^4*x^m/prod(k=1,m,1+k^4*x+x*O(x^n))),n)}

a(n) = A(n-1, 1) for the above Gandhi polynomials.

O.g.f.: Sum_{n>=0} n!^4 * x^n / Product_{k=1..n} (1 + k^4*x). [From Paul D. Hanna, Jul 21 2011]

A099960 An interleaving of the Genocchi numbers of the first and second kind, A110501 and A005439.

Original entry on oeis.org

1, 1, 1, 1, 2, 3, 8, 17, 56, 155, 608, 2073, 9440, 38227, 198272, 929569, 5410688, 28820619, 186043904, 1109652905, 7867739648, 51943281731, 401293838336, 2905151042481, 24290513745920, 191329672483963, 1721379917619200, 14655626154768697, 141174819474169856

Offset: 0

N. J. A. Sloane, Nov 13 2004

First column (also row sums) of triangle in A099959.

Number of ascent sequences of length n without level steps and with alternating ascents and descents. a(6) = 8: 010101, 010102, 010103, 010201, 010202, 010203, 010212, 010213. - Alois P. Heinz, Oct 27 2017

Donald E. Knuth, The Art of Computer Programming, Vol. 4, fascicle 1, section 7.1.4, p. 220, answer to exercise 174, Addison-Wesley, 2009.

Alois P. Heinz, Table of n, a(n) for n = 0..500
Catalin Zara, Cardinality of l_1-Segments and Genocchi Numbers, arXiv:1304.5798 [math.CO] (2013)

Cf. A022493, A099959, A001469, A005439, A138265, A294281.

with(linalg):rev:=proc(a) local n, p; n:=vectdim(a): p:=i->a[n+1-i]: vector(n,p) end: ps:=proc(a) local n, q; n:=vectdim(a): q:=i->sum(a[j],j=1..i): vector(n,q) end: pss:=proc(a) local n, q; n:=vectdim(a): q:=proc(i) if i<=n then sum(a[j],j=1..i) else sum(a[j],j=1..n) fi end: vector(n+1,q) end: R[0]:=vector(1,1): for n from 1 to 30 do if n mod 2 = 1 then R[n]:=ps(rev(R[n-1])) else R[n]:=pss(rev(R[n-1])) fi od: seq(R[n][1],n=0..30); # Emeric Deutsch

g1 = Table[2*(4^n-1)*BernoulliB[2*n] // Abs, {n, 0, 13}]; g2 = Table[2*(-1)^(n-2)*Sum[Binomial[n, k]*(1-2^(n+k+1))*BernoulliB[n+k+1], {k, 0, n}], {n, 0, 13}]; Riffle[g1, g2] // Rest (* Jean-François Alcover, May 23 2013 *)

# Algorithm of L. Seidel (1877)
def A099960_list(n) :
    D = [0]*(n//2+3); D[1] = 1
    R = []; b = True; h = 1
    for i in (1..n) :
        if b :
            for k in range(h,0,-1) : D[k] += D[k+1]
            R.append(D[1]); h += 1
        else :
            for k in range(1,h, 1) : D[k] += D[k-1]
            R.append(D[h-1])
        b = not b
    return R
A099960_list(27)  # Peter Luschny, Apr 30 2012

a(n) ~ 2^(5/2) * n^(n+3/2) / (Pi^(n+1/2) * exp(n)). - Vaclav Kotesovec, Sep 10 2014

More terms from Emeric Deutsch, Nov 16 2004

A104030 Matrix inverse, read by rows, of triangle A104029, which forms the pairwise sums of trinomial coefficients.

Original entry on oeis.org

1, -2, 1, 7, -5, 1, -41, 32, -9, 1, 376, -299, 91, -14, 1, -5033, 4015, -1241, 205, -20, 1, 92821, -74080, 22954, -3842, 400, -27, 1, -2257166, 1801537, -558402, 93652, -9863, 707, -35, 1, 69981919, -55855829, 17313721, -2904530, 306409, -22190, 1162, -44, 1, -2694447797, 2150565968

Offset: 0

Paul D. Hanna, Feb 26 2005

Column 0 forms signed Hammersley's polynomial p_n(1) (A006846), offset 1.
Row sums equal negative Genocchi numbers of first kind (A001469).
Rows form polynomials R_n(x) such that: R_n(3) = 1 for n>=0 and R_n(1/2) = (-1)^n*A005647(n+1)/2^n (signed Salie numbers).
Column 1 forms A104031.
Unsigned row sums form A104032.

			Rows begin:
1;
-2,1;
7,-5,1;
-41,32,-9,1;
376,-299,91,-14,1;
-5033,4015,-1241,205,-20,1;
92821,-74080,22954,-3842,400,-27,1;
-2257166,1801537,-558402,93652,-9863,707,-35,1; ...

Cf. A006846, A001469, A005647, A104027, A104029, A104031, A104032.

T(n,k)=if(n=j, polcoeff((1+x+x^2)^(m-1)+O(x^(2*j)),2*j-2)+ polcoeff((1+x+x^2)^(m-1)+O(x^(2*j)),2*j-1))))^-1)[n+1,k+1])

A224783 Denominator of Bernoulli(n,1/2) - Bernoulli(n,0).

Original entry on oeis.org

1, 2, 4, 1, 16, 1, 64, 1, 256, 1, 1024, 1, 4096, 1, 16384, 1, 65536, 1, 262144, 1, 1048576, 1, 4194304, 1, 16777216, 1, 67108864, 1, 268435456, 1, 1073741824, 1, 4294967296, 1, 17179869184, 1, 68719476736, 1, 274877906944, 1, 1099511627776

Offset: 0

Paul Curtz, Apr 17 2013

See A157779 and A157780 for values of Bernoulli(n,1/2), and A027641 and A027642 for values of Bernoulli(n,0).
B(n,1/2) - B(n,0) = 0, 1/2, -1/4, 0, 1/16, 0, -3/64, 0, 17/256, 0, -155/1024, 0, 2073/4096, 0, -38227/16384,... for n>=0.
The sequence of numerators is 0, 1, -1, 0, 1, 0, -3, 0, 17, 0, -155, 0, 2073, 0, -38227, 0, 929569, 0, -28820619, 0, 1109652905,...and appears to contain a mix of A001469 and A036968.

			a(0) = 1-1, a(1) = 0+1/2, a(2) = -1/12-1/6=-1/4.

Vincenzo Librandi, Table of n, a(n) for n = 0..250
Index entries for linear recurrences with constant coefficients, signature (0,5,0,-4).

Cf. A001469, A027641, A027642, A036968, A059222, A157779, A157780.

A224783 := proc(n)
    bernoulli(n,1/2)-bernoulli(n) ;
    denom(%) ;
end proc: # R. J. Mathar, Apr 25 2013

Table[Denominator[BernoulliB[n, 1/2] - BernoulliB[n, 0]], {n, 0, 50}] (* Vincenzo Librandi, Mar 19 2014 *)

Vec((4*x^5-9*x^3-x^2+2*x+1)/((x-1)*(x+1)*(2*x-1)*(2*x+1)) + O(x^100)) \\ Colin Barker, Mar 20 2014

a(n) = A059222(n+1) if n <> 1.
From Colin Barker, Mar 19 2014: (Start)
G.f.: (4*x^5-9*x^3-x^2+2*x+1) / ((x-1)*(x+1)*(2*x-1)*(2*x+1)).
a(n) = 5*a(n-2)-4*a(n-4) for n>5.
a(n) = (1+(-2)^n-(-1)^n+2^n)/2 for n>1. (End).

A005440 Coefficients of Gandhi polynomials.

Original entry on oeis.org

2, 8, 54, 556, 8146, 161424, 4163438, 135634292, 5448798090, 264689281240, 15296907175462, 1037373202178748, 81588771795362114, 7366855482991121696, 756909709680583939806, 87807399365909591247364

Offset: 2

N. J. A. Sloane, Simon Plouffe

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Robert Israel, Table of n, a(n) for n = 2..275
D. Dumont, Interprétations combinatoires des nombres de Genocchi, Duke Math. J., 41 (1974), 305-318.
D. Dumont, Interprétations combinatoires des nombres de Genocchi, Duke Math. J., 41 (1974), 305-318. (Annotated scanned copy)

Second column in table A036970.

B[1]:= X -> X^2:
for n from 2 to 50 do B[n]:= unapply(expand(X^2*(B[n-1](X+1)-B[n-1](X))), X) od:
seq(D(B[n])(1),n=1..50); # Robert Israel, Apr 21 2016

More terms from David W. Wilson, Jan 12 2001

A012509 E.g.f.: -log(cos(x)*cos(x)) (even powers only).

Original entry on oeis.org

0, 2, 4, 32, 544, 15872, 707584, 44736512, 3807514624, 419730685952, 58177770225664, 9902996106248192, 2030847773013704704, 493842960380415967232, 140503203207887919775744, 46238368375619195682947072, 17427925514250338592341622784, 7458815407441059142195019251712

Offset: 0

Patrick Demichel (patrick.demichel(AT)hp.com)

nonn

Of course this is 2*log(sec(x)), so a(n) = 2*A000182(n).

			G.f. = x^2+1/6*x^4+2/45*x^6+17/1260*x^8+62/14175*x^10+691/467775*x^12+...

Tewodros Amdeberhan, Victor H. Moll and Christophe Vignat, A probabilistic interpretation of a sequence related to Narayana Polynomials, arXiv:1202.1203 [math.NT], 2012. See p. 21.
Tewodros Amdeberhan, Victor H. Moll and Christophe Vignat, A probabilistic interpretation of a sequence related to Narayana Polynomials, Online Journal of Analytic Combinatorics, Issue 8, 2013. See p. 21.
N. J. A. Sloane, Rough notes on Genocchi numbers

Cf. A000182.

nn = 20; Table[(CoefficientList[Series[-Log[Cos[x]^2], {x, 0, 2*nn}], x] * Range[0, 2*nn]!)[[n]], {n, 1, 2*nn+1, 2}] (* Vaclav Kotesovec, Feb 08 2015 *)

G.f.: 2/Q(0) where Q(k) = 1 + x*(2*k + 1)*(2*k + 2)/( -1 + x*(2*k + 2)*(2*k + 3)/Q(k+1) ); (continued fraction). - Sergei N. Gladkovskii, Mar 11 2013
G.f.: (2/G(0) - 1)*sqrt(-x), where G(k)= 2 + 2*sqrt(-x) - 4*x*(k+1)^2/G(k+1); (continued fraction). - Sergei N. Gladkovskii, May 29 2013
G.f.: 2*x*T(0), where T(k) = 1 - (k+1)*(k+2)*x/((k+1)*(k+2)*x - 1/T(k+1) ); (continued fraction). - Sergei N. Gladkovskii, Nov 15 2013
a(n) ~ 2^(2*n+2) * (2*n-1)! / Pi^(2*n). - Vaclav Kotesovec, Feb 08 2015
E.g.f. (odd powers): y = 2*tan(x). - Stanislav Sykora, Nov 28 2016

Corrected by D. S. McNeil and N. J. A. Sloane, Dec 17 2011 (The signs were wrong and the initial term was missing)

A014781 Seidel's triangle, read by rows.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 2, 3, 3, 8, 6, 3, 8, 14, 17, 17, 56, 48, 34, 17, 56, 104, 138, 155, 155, 608, 552, 448, 310, 155, 608, 1160, 1608, 1918, 2073, 2073, 9440, 8832, 7672, 6064, 4146, 2073, 9440, 18272, 25944, 32008, 36154, 38227

Offset: 1

N. J. A. Sloane

Named after the German mathematician Philipp Ludwig von Seidel (1821-1896). - Amiram Eldar, Jun 13 2021

			Triangle begins:
     1;
     1;
     1,    1;
     2,    1;
     2,    3,    3;
     8,    6,    3;
     8,   14,   17,   17;
    56,   48,   34,   17;
    56,  104,  138,  155,  155;
   608,  552,  448,  310,  155;
   608, 1160, 1608, 1918, 2073, 2073;
  9440, 8832, 7672, 6064, 4146, 2073;
  ...

Bishal Deb and Alan D. Sokal, Classical continued fractions for some multivariate polynomials generalizing the Genocchi and median Genocchi numbers, arXiv:2212.07232 [math.CO], 2022. See p. 13.
Dominique Dumont and Arthur Randrianarivony, Dérangements et nombres de Genocchi, Discrete Math., Vol. 132, No. 1-3 (1994), pp. 37-49.
Dominique Dumont and Jiang Zeng, Polynomes d'Euler et fractions continues de Stieltjes-Rogers, The Ramanujan Journal, Vol. 2, No. 3 (1998), pp. 387-410; alternative link.
Richard Ehrenborg and Einar Steingrímsson, Yet another triangle for the Genocchi numbers, European J. Combin., Vol. 21, No. 5 (2000), pp. 593-600. MR1771988 (2001h:05008).
Evgeny Feigin, The median Genocchi numbers, q-analogues and continued fractions, European Journal of Combinatorics, Vol. 33, No. 8 (2012), pp. 1913-1918; arXiv preprint, arXiv:1111.0740 [math.CO], 2011-2012.
Guo-Niu Han and Jiang Zeng, On a q-sequence that generalizes the median Genocchi numbers, Annal Sci. Math. Québec, Vol. 23, No. 1 (1999), pp. 63-72.
Peter Luschny, An old operation on sequences: the Seidel transform.
Qiongqiong Pan and Jiang Zeng, Cycles of even-odd drop permutations and continued fractions of Genocchi numbers, arXiv:2108.03200 [math.CO], 2021.
Ludwig Seidel, Über eine einfache Entstehungsweise der Bernoulli'schen Zahlen und einiger verwandten Reihen, Sitzungsberichte der mathematisch-physikalischen Classe der königlich bayerischen Akademie der Wissenschaften zu München, Vol. 7 (1877), pp. 157-187.

Even terms of first column give A005439. Diagonal gives A001469.

Cf. A005439, A001469.

max = 13; T[1, 1] = 1; T[n_, k_] /; 1 <= k <= (n+1)/2 := T[n, k] = If[EvenQ[n], Sum[T[n-1, i], {i, k, max}], Sum[T[n-1, i], {i, 1, k}]]; T[, ] = 0; Table[T[n, k], {n, 1, max}, {k, 1, (n+1)/2}] // Flatten (* Jean-François Alcover, Nov 18 2016 *)

# Algorithm of L. Seidel (1877)
# n -> Prints first n rows of the triangle
def A014781_triangle(n) :
    D = []; [D.append(0) for i in (0..n)]; D[1] = 1
    b = True
    for i in(0..n) :
        h = (i-1)//2 + 1
        if b :
            for k in range(h-1,0,-1) : D[k] += D[k+1]
        else :
            for k in range(1,h+1,1) :  D[k] += D[k-1]
        b = not b
        if i>0 : print([D[z] for z in (1..h)])
A014781_triangle(12) # Peter Luschny, Apr 01 2012

More terms from Mike Domaratzki (mdomaratzki(AT)alumni.uwaterloo.ca), Nov 18 2001

A065748 Triangle of Gandhi polynomial coefficients.

Original entry on oeis.org

1, 1, 4, 6, 4, 15, 88, 220, 304, 250, 120, 28, 1025, 7308, 23234, 43420, 52880, 43880, 25088, 9680, 2340, 280, 209135, 1691024, 6237520, 13911400, 20956610, 22549360, 17853780, 10541440, 4639740, 1498280, 341000, 49920, 3640, 100482849

Offset: 1

Mike Domaratzki (mdomaratzki(AT)alumni.uwaterloo.ca), Nov 16 2001

First column is A064625.

			Triangle starts
1;
1,4,6,4;
15,88,220,304,250,120,28;
1025,...

Michael Domaratzki, Combinatorial Interpretations of a Generalization of the Genocchi Numbers, Journal of Integer Sequences, Vol. 7 (2004), Article 04.3.6.
D. Dumont, Sur une conjecture de Gandhi concernant les nombres de Genocchi, (in French), Discrete Mathematics 1 (1972) 321-327.
D. Dumont, Interprétations combinatoires des nombres de Genocchi, Duke Math. J., 41 (1974), 305-318.
D. Dumont, Interprétations combinatoires des nombres de Genocchi, Duke Math. J., 41 (1974), 305-318. (Annotated scanned copy)

Cf. A064625, A036970

Let B(X, n) = X^4 (B(X+1, n-1) - B(X, n-1)), B(X, 1) = X^4; then the (i, j)-th entry in the table is the coefficient of X^(5+j) in B(X, i).

A090681 Expansion of (sec(x/2)^2 + sech(x/2)^2)/2 in powers of x^4.

Original entry on oeis.org

1, 1, 31, 5461, 3202291, 4722116521, 14717667114151, 86125672563201181, 868320396104950823611, 14129659550745551130667441, 352552873457246307069012458671, 12942188000689093683411117827763301, 675618013651758631167025175564066787331, 48743995308245045290420262686473639399176761

Offset: 0

Benoit Cloitre, Dec 18 2003

nonn

			(sec(x/2)^2 + sech(x/2)^2)/2 = 1 + x^4/4! + 31*x^8/8! + 5461*x^12/12! + ...

Stefano Spezia, Table of n, a(n) for n = 0..135

Cf. A001469, A002425, A012670, A012853.

[2*(4^(2*n+1) -1)*BernoulliNumber(4*n+2)/(2*n+1): n in [0..15]]; // G. C. Greubel, Jun 28 2019

a := n->(2*2^(4*n+2)-2)*bernoulli(4*n+2)/(2*n+1): seq(a(n), n = 0 .. 15); # Stefano Spezia, Jun 14 2019

a[n_]:=2*(2^(4*n+2)-1)*BernoulliB[4*n+2]/(2*n+1); Array[a,15,0] (* Stefano Spezia, Jun 14 2019 *)

a(n)=if(n<0,0,n*=4;n!*polcoeff(1/cosh(x/2+x*O(x^n))^2+1/cos(x/2+x*O(x^n))^2,n)/2) /* Michael Somos, Mar 06 2004 */

a(n)=if(n<0,0,n=4*n+2;4*(2^n-1)*bernfrac(n)/n) /* Michael Somos, Mar 06 2004 */

[2*(4^(2*n+1)-1)*bernoulli(4*n+2)/(2*n+1) for n in (0..15)] # G. C. Greubel, Jun 28 2019

a(n) = -G(2n+1)/(2n+1) where G(k) is the k-th Genocchi number of first kind (A001469).
a(n) = A002425(2n+1).
a(n) = A012853(n)/2^(4n+1).
a(n) = abs(A012670(n)/2^(6n+1)).
E.g.f.: (sec(x/2)^2 + sech(x/2)^2)/2 = Sum_{k>=1} a(k)*x^(4k)/(4k)!. - Michael Somos, Mar 06 2004
a(n) == 1 (mod 30). - Michael Somos, Jul 23 2005

cp's OEIS Frontend

A064624 Generalization of the Genocchi numbers given by the Gandhi polynomials A(n+1,r) = r^3 A(n, r + 1) - (r - 1)^3 A(n, r); A(1,r) = r^3 - (r-1)^3.

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A064625 Generalization of the Genocchi numbers. Generated by the Gandhi polynomials A(n+1,r) = r^4 A(n,r+1) - (r-1)^4 A(n,r); A(1,r) = r^4 - (r-1)^4.

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A099960 An interleaving of the Genocchi numbers of the first and second kind, A110501 and A005439.

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A104030 Matrix inverse, read by rows, of triangle A104029, which forms the pairwise sums of trinomial coefficients.

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A224783 Denominator of Bernoulli(n,1/2) - Bernoulli(n,0).

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A005440 Coefficients of Gandhi polynomials.

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A012509 E.g.f.: -log(cos(x)*cos(x)) (even powers only).

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