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.

Previous Showing 11-18 of 18 results.

A085737 Numerators in triangle formed from Bernoulli numbers.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 0, 1, 1, 0, -1, 1, 2, 1, -1, 0, -1, 1, 1, -1, 0, 1, -1, -1, 8, -1, -1, 1, 0, 1, -1, 4, 4, -1, 1, 0, -1, 1, -1, -4, 8, -4, -1, 1, -1, 0, -1, 1, -8, 4, 4, -8, 1, -1, 0, 5, -5, 7, 4, -116, 32, -116, 4, 7, -5, 5, 0, 5, -5, 32, -28, 16, 16, -28, 32, -5, 5, 0
Offset: 0

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Author

N. J. A. Sloane, following a suggestion of J. H. Conway, Jul 23 2003

Keywords

Comments

Triangle is determined by rules 0) the top number is 1; 1) each number is the sum of the two below it; 2) it is left-right symmetric; 3) the numbers in each of the border rows, after the first 3, are alternately 0.
Up to signs this is the difference table of the Bernoulli numbers (see A212196). The Sage script below is based on L. Seidel's algorithm and does not make use of a library function for the Bernoulli numbers; in fact it generates the Bernoulli numbers on the fly. - Peter Luschny, May 04 2012

Examples

			Triangle of fractions begins
    1;
   1/2,   1/2;
   1/6,   1/3,   1/6;
    0,    1/6,   1/6,     0;
  -1/30,  1/30,  2/15,   1/30,  -1/30;
    0,   -1/30,  1/15,   1/15,  -1/30,    0;
   1/42, -1/42, -1/105,  8/105, -1/105, -1/42,   1/42;
    0,    1/42, -1/21,   4/105,  4/105, -1/21,   1/42,   0;
  -1/30,  1/30, -1/105, -4/105,  8/105, -4/105, -1/105, 1/30, -1/30;
		

Crossrefs

Cf. A085738, A212196. See A051714/A051715 for another triangle that generates the Bernoulli numbers.

Programs

  • Maple
    nmax:=11; for n from 0 to nmax do T(n, 0):= (-1)^n*bernoulli(n) od: for n from 1 to nmax do for k from 1 to n do  T(n, k) := T(n-1, k-1) - T(n, k-1) od: od: for n from 0 to nmax do seq(T(n, k), k=0..n) od: seq(seq(numer(T(n, k)), k=0..n), n=0..nmax);  # Johannes W. Meijer, Jun 29 2011, revised Nov 25 2012
  • Mathematica
    t[n_, 0] := (-1)^n*BernoulliB[n]; t[n_, k_] := t[n, k] = t[n-1, k-1] - t[n, k-1]; Table[t[n, k] // Numerator, {n, 0, 11}, {k, 0, n}] // Flatten (* Jean-François Alcover, Jan 07 2014 *)
  • Sage
    def BernoulliDifferenceTable(n) :
        def T(S, a) :
            R = [a]
            for s in S :
                a -= s
                R.append(a)
            return R
        def M(A, p) :
            R = T(A,0)
            S = add(r for r in R)
            return -S / (2*p+3)
        R = [1/1]
        A = [1/2,-1/2]; R.extend(A)
        for k in (0..n-2) :
            A = T(A,M(A,k)); R.extend(A)
            A = T(A,0); R.extend(A)
        return R
    def A085737_list(n) : return [numerator(q) for q in BernoulliDifferenceTable(n)]
    # Peter Luschny, May 04 2012

Formula

T(n, 0) = (-1)^n*Bernoulli(n), T(n, k) = T(n-1, k-1) - T(n, k-1) for k=1..n.
T(n,k) = Sum_{j=0..k} binomial(k,j)*Bernoulli(n-j). [Lange and Grabisch]

Extensions

Sign flipped in formula by Johannes W. Meijer, Jun 29 2011

A191302 Denominators in triangle that leads to the Bernoulli numbers.

Original entry on oeis.org

1, 2, 2, 3, 2, 2, 2, 3, 15, 2, 6, 3, 2, 1, 5, 105, 2, 6, 15, 15, 2, 3, 3, 105, 105, 2, 2, 5, 7, 35, 2, 3, 3, 21, 21, 231, 2, 6, 15, 15, 21, 21, 2, 1, 5, 15, 1, 77, 15015, 2, 6, 3, 35, 15, 33, 1155
Offset: 0

Views

Author

Paul Curtz, May 30 2011

Keywords

Comments

For the definition of the ASPEC array coefficients see the formulas; see also A029635 (Lucas triangle), A097207 and A191662 (k-dimensional square pyramidal numbers).
The antidiagonal row sums of the ASPEC array equal A042950(n) and A098011(n+3).
The coefficients of the T(n,m) array are defined in A190339. We define the coefficients of the SBD array with the aid of the T(n,n+1), see the formulas and the examples.
Multiplication of the coefficients in the rows of the ASPEC array with the coefficients in the columns of the SBD array leads to the coefficients of the BSPEC triangle, see the formulas. The BSPEC triangle can be looked upon as a spectrum for the Bernoulli numbers.
The row sums of the BSPEC triangle give the Bernoulli numbers A164555(n)/A027642(n).
For the numerators of the BSPEC triangle coefficients see A192456.

Examples

			The first few rows of the array ASPEC array:
  2, 1,  1,  1,   1,   1,    1,
  2, 3,  4,  5,   6,   7,    8,
  2, 5,  9, 14,  20,  27,   35,
  2, 7, 16, 30,  50,  77,  112,
  2, 9, 25, 55, 105, 182,  294,
The first few T(n,n+1) = T(n,n)/2 coefficients:
1/2, -1/6, 1/15, -4/105, 4/105, -16/231, 3056/15015, ...
The first few rows of the SBD array:
  1/2,   0,   0,     0
  1/2,   0,   0,     0
  1/2, -1/6,  0,     0
  1/2, -1/6,  0,     0
  1/2, -1/6, 1/15,   0
  1/2, -1/6, 1/15,   0
  1/2, -1/6, 1/15, -4/105
  1/2, -1/6, 1/15, -4/105
The first few rows of the BSPEC triangle:
  B(0) =   1   = 1/1
  B(1) =  1/2  = 1/2
  B(2) =  1/6  = 1/2 - 1/3
  B(3) =   0   = 1/2 - 1/2
  B(4) = -1/30 = 1/2 - 2/3 +  2/15
  B(5) =   0   = 1/2 - 5/6 +  1/3
  B(6) =  1/42 = 1/2 - 1/1 +  3/5  - 8/105
  B(7) =   0   = 1/2 - 7/6 + 14/15 - 4/15
		

Crossrefs

Cf. A028246 (Worpitzky), A085737/A085738 (Conway-Sloane) and A051714/A051715 (Akiyama-Tanigawa) for other triangles that lead to the Bernoulli numbers. - Johannes W. Meijer, Jul 02 2011

Programs

  • Maple
    nmax:=13: mmax:=nmax:
    A164555:=proc(n): if n=1 then 1 else numer(bernoulli(n)) fi: end:
    A027642:=proc(n): if n=1 then 2 else denom(bernoulli(n)) fi: end:
    for m from 0 to 2*mmax do T(0,m):=A164555(m)/A027642(m) od:
    for n from 1 to nmax do for m from 0 to 2*mmax do T(n,m):=T(n-1,m+1)-T(n-1,m) od: od:
    seq(T(n,n+1),n=0..nmax):
    for n from 0 to nmax do ASPEC(n,0):=2: for m from 1 to mmax do ASPEC(n,m):= (2*n+m)*binomial(n+m-1,m-1)/m od: od:
    for n from 0 to nmax do seq(ASPEC(n,m),m=0..mmax) od:
    for n from 0 to nmax do for m from 0 to 2*mmax do SBD(n,m):=0 od: od:
    for m from 0 to mmax do for n from 2*m to nmax do SBD(n,m):= T(m,m+1) od: od:
    for n from 0 to nmax do seq(SBD(n,m), m= 0..mmax/2) od:
    for n from 0 to nmax do BSPEC(n,2) := SBD(n,2)*ASPEC(2,n-4) od:
    for m from 0 to mmax do for n from 0 to nmax do BSPEC(n,m) := SBD(n,m)*ASPEC(m,n-2*m) od: od:
    for n from 0 to nmax do seq(BSPEC(n,m), m=0..mmax/2) od:
    seq(add(BSPEC(n, k), k=0..floor(n/2)) ,n=0..nmax):
    Tx:=0:
    for n from 0 to nmax do for m from 0 to floor(n/2) do a(Tx):= denom(BSPEC(n,m)): Tx:=Tx+1: od: od:
    seq(a(n),n=0..Tx-1); # Johannes W. Meijer, Jul 02 2011
  • Mathematica
    (* a=ASPEC, b=BSPEC *) nmax = 13; a[n_, 0] = 2; a[n_, m_] := (2n+m)*Binomial[n+m-1, m-1]/m; b[n_] := BernoulliB[n]; b[1]=1/2; bb = Table[b[n], {n, 0, nmax}]; diff = Table[ Differences[bb, n], {n, 1, nmax}]; dd = Diagonal[diff]; sbd[n_, m_] := If[n >= 2m, -dd[[m+1]], 0]; b[n_, m_] := sbd[n, m]*a[m, n-2m]; Table[b[n, m], {n, 0, nmax}, {m, 0, Floor[n/2]}] // Flatten // Denominator (* Jean-François Alcover_, Aug 09 2012 *)

Formula

ASPEC(n, 0) = 2 and ASPEC(n, m) = (2*n+m)*binomial(n+m-1, m-1)/m, n >= 0, m >= 1.
ASPEC(n, m) = ASPEC(n-1, m) + ASPEC(n, m-1), n >= 1, m >= 1, with ASPEC(n, 0) = 2, n >= 0, and ASPEC(0,m) = 1, m >= 1.
SBD(n, m) = T(m, m+1), n >= 2*m; see A190339 for the definition of the T(n, m).
BSPEC(n, m) = SBD(n, m)*ASPEC(m, n-2*m)
Sum_{k=0..floor(n/2)} BSPEC(n, k) = A164555(n)/A027642(n).

Extensions

Edited, Maple program and crossrefs added by Johannes W. Meijer, Jul 02 2011

A051712 Numerator of b(n)-b(n+1), where b(n) = n/((n+1)(n+2)) = A026741/A045896.

Original entry on oeis.org

0, 1, 1, 1, 1, 5, 1, 7, 1, 3, 5, 11, 1, 13, 7, 5, 2, 17, 3, 19, 5, 7, 11, 23, 1, 25, 13, 9, 7, 29, 5, 31, 4, 11, 17, 35, 3, 37, 19, 13, 5, 41, 7, 43, 11, 15, 23, 47, 2, 49, 25, 17, 13, 53, 9, 55, 7, 19, 29, 59, 5, 61, 31, 21, 8, 65, 11, 67, 17, 23, 35, 71, 3, 73
Offset: 1

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Author

Keywords

Examples

			0, 1/60, 1/60, 1/70, 1/84, 5/504, 1/120, 7/990, 1/165, 3/572,...
		

Crossrefs

Row 3 of table in A051714/A051715.

Programs

  • Mathematica
    b[n_] := n/((n + 1) (n + 2)); Numerator[-Differences[Array[b, 100]]]
    (* or *)
    f[p_, e_] := p^e; f[2, e_] := If[e < 3, 1, 2^(e - 3)]; f[3, e_] := 3^(e - 1); a[1] = 0; a[n_] := Times @@ f @@@ FactorInteger[n - 1]; Array[a, 100] (* Amiram Eldar, Nov 20 2022 *)

Formula

c(n) = a(n+1) is multiplicative with c(2^e) = 2^(e-3) if e > 2 and 1 otherwise, c(3^e) = 3^(e-1), and c(p^e) = p^e if p >= 5. [corrected by Amiram Eldar, Nov 20 2022]
Sum_{k=1..n} a(k) ~ (301/1152) * n^2. - Amiram Eldar, Nov 20 2022

A051713 Denominator of b(n)-b(n+1), where b(n) = n/((n+1)(n+2)) = A026741/A045896.

Original entry on oeis.org

1, 60, 60, 70, 84, 504, 120, 990, 165, 572, 1092, 2730, 280, 4080, 2448, 1938, 855, 7980, 1540, 10626, 3036, 4600, 7800, 17550, 819, 21924, 12180, 8990, 7440, 32736, 5984, 39270, 5355, 15540, 25308, 54834, 4940, 63960, 34440
Offset: 1

Views

Author

Keywords

Examples

			0, 1/60, 1/60, 1/70, 1/84, 5/504, 1/120, 7/990, 1/165, 3/572,...
		

Crossrefs

Cf. A051712. Row 3 of table in A051714/A051715.

Programs

  • Mathematica
    Denominator[#[[1]]-#[[2]]&/@(Partition[#[[1]]/(#[[2]]#[[3]])&/@Partition[ Range[50],3,1],2,1])] (* Harvey P. Dale, Nov 15 2014 *)

A362991 Triangle read by rows. T(n, k) = lcm{1, 2, ..., n+1} * Sum_{j=0..n-k} (-1)^(n-k-j) * j! * Stirling2(n - k, j) / (j + k + 1).

Original entry on oeis.org

1, 1, 1, 1, 2, 2, 0, 2, 3, 3, -2, 2, 9, 12, 12, 0, -2, 3, 8, 10, 10, 10, -10, -9, 24, 50, 60, 60, 0, 20, -30, -8, 50, 90, 105, 105, -84, 84, 18, -96, 0, 150, 245, 280, 280, 0, -84, 126, -24, -90, 18, 147, 224, 252, 252, 2100, -2100, 126, 1344, -600, -870, 343, 1568, 2268, 2520, 2520
Offset: 0

Views

Author

Peter Luschny, May 16 2023

Keywords

Comments

A variant of the Akiyama-Tanigawa algorithm for the Bernoulli numbers A164555/ A027642.

Examples

			Triangle T(n, k) starts:
[0]   1;
[1]   1,   1;
[2]   1,   2,   2;
[3]   0,   2,   3,   3;
[4]  -2,   2,   9,  12,  12;
[5]   0,  -2,   3,   8,  10,  10;
[6]  10, -10,  -9,  24,  50,  60,  60;
[7]   0,  20, -30,  -8,  50,  90, 105, 105;
[8] -84,  84,  18, -96,   0, 150, 245, 280, 280;
[9]   0, -84, 126, -24, -90,  18, 147, 224, 252, 252;
		

Crossrefs

Variant: A051714/A051715.
Cf. A362994 (column 0), A002944 (main diagonal), A164555/A027642 (Bernoulli).

Programs

  • Maple
    LCM := n -> ilcm(seq((1 + i), i = 0..n)):
    T := (n, k) -> LCM(n)*add((-1)^(n - k - j)*j!*Stirling2(n - k, j)/(j + k + 1), j = 0..n - k):
    for n from 0 to 9 do seq(T(n, k), k = 0..n) od;
  • Mathematica
    A362991row[n_]:=Table[LCM@@Range[n+1]Sum[(-1)^(n-k-j)j!StirlingS2[n-k,j]/(j+k+1),{j,0,n-k}],{k,0,n}];Array[A362991row,15,0] (* Paolo Xausa, Aug 09 2023 *)
  • SageMath
    def A362991Triangle(size):  # 'size' is the number of rows.
        A, T, l = [], [], 1
        for n in range(size):
            A.append(Rational(1/(n + 1)))
            for j in range(n, 0, -1):
                A[j - 1] = j * (A[j - 1] - A[j])
            l = lcm(l, n + 1)
            T.append([a * l for a in A])
        return T
    A362991Triangle(10)

Formula

T(n, 0) = lcm(1, 2, ..., n+1) * Bernoulli(n, 1).

A244605 Numerators of the Akiyama-Tanigawa transform applied to 1/(n+1) with -1/2 instead of 1/2.

Original entry on oeis.org

1, 3, 19, 7, 449, 31, 2647, 127, 7649, 511, 67523, 2047, 11178659, 8191, 98305, 32767, 33419233, 131071, 209233981, 524287, 345855139, 2097151, 579668327, 8388607, 45565432859, 33554431, 411206281, 134217727, 209789384821, 536870911, 23993971665011, 2147483647, -5518887720767
Offset: 0

Views

Author

Paul Curtz, Jul 01 2014

Keywords

Comments

The autosequence of the second kind A164555(n)/A027642(n) = 1, 1/2, 1/6, 0, -1/30, 0, ... (the second Bernoulli numbers) is the binomial transform of A027641(n)/A027642(n) = 1, -1/2, 1/6, 0, -1/30, 0, ... (the first Bernoulli numbers). Hence the name.
The Akiyama-Tanigawa transform applied to 1, -1/2, 1/3, 1/4, 1/5, 1/6, ... is:
1, -1/2, 1/3, 1/4, 1/5, ...
3/2, -5/3, 1/4, 1/5, 1/6, ...
19/6, -23/6, 3/20, 2/15, 5/42, ...
7, -239/30, 1/20, 2/35, 5/84, ... .
The first column is a(n)/b(n) = 1, 3/2, 19/6, 7, 449/30, 31, 2647/42, 127, 7649/30, 511, 67523/66, 2047, ..., where the denominators are b(n) = A027642(n).
By the formula below, the Bernoulli numbers are linked to the Mersenne numbers A000225 (2^n-1).

Crossrefs

Programs

  • Mathematica
    a[n_] := BernoulliB[n]+2^n-1 // Numerator; a[1] = 3; Table[a[n], {n, 0, 32}] (* Jean-François Alcover, Jul 25 2014 *)
  • PARI
    a(n) = my(b = numerator(bernfrac(n))/denominator(bernfrac(n))); if (n == 1, numerator(- b + 2^n - 1), numerator(b + 2^n - 1)); \\ Michel Marcus, Jul 18 2014
    
  • PARI
    {a(n) = if( n<0, 0, 2*(n==1) + numerator( bernfrac(n) + 2^n - 1))}; /* Michael Somos, Aug 05 2014 */

Formula

a(n) = numerator of A164555(n)/A027642(n) + A000225(n).

Extensions

a(12)-a(32) from Jean-François Alcover, Jul 01 2014

A182397 Numerators in triangle that leads to the (first) Bernoulli numbers A027641/A027642.

Original entry on oeis.org

1, 1, -3, 1, -5, 5, 1, -7, 25, -5, 1, -9, 23, -35, 49, 1, -11, 73, -27, 112, -49, 1, -13, 53, -77, 629, -91, 58, 1, -15, 145, -130, 1399, -451, 753, -58, 1, -17, 95, -135, 2699, -2301, 8573, -869, 341, 1, -19, 241
Offset: 0

Views

Author

Paul Curtz, Apr 27 2012

Keywords

Comments

In A190339 we saw that (the second Bernoulli numbers) A164555/A027642 is an eigensequence (its inverse binomial transform is the sequence signed) of the second kind, see A192456/A191302. We consider this array preceded by 1 for the second row, by 1, -3/2, for the third one; 1 is chosen and is followed by the differences of successive rows.
Hence
1 1/2 1/6 0
1 -1/2 -1/3 -1/6 -1/30
1 -3/2 1/6 1/6 2/15 1/15
1 -5/2 5/3 0 -1/30 -1/15 -8/105.
The second row is A051716/A051717.
The (reduced) triangle before the square array (T(n,m) in A190339) is a(n)/b(n)=
B(0)= 1 = 1 Redbernou1li
B(1)= -1/2 = 1 -3/2
B(2)= 1/6 = 1 -5/2 5/3
B(3)= 0 = 1 -7/2 25/6 -5/3
B(4)=-1/30 = 1 -9/2 23/3 -35/6 49/30
B(5)= 0 = 1 -11/2 73/6 -27/2 112/15 -49/30.
For the main diagonal, see A165142.
Denominator b(n) will be submitted.
This transform is valuable for every eigensequence of the second kind. For instance Leibniz's 1/n (A003506).
With increasing exponents for coefficients, polynomials CB(n,x) create Redbernou1li. See the formula.
Triangle Bernou1li for A027641/A027642 with the same denominator A080326 for every column is
1
1 -3/2
1 -5/2 10/6
1 -7/2 25/6 -10/6
1 -9/2 46/6 -35/6 49/30
1 -11/2 73/6 -81/6 224/30 -49/30.
For numerator by columns,see A000012, -A144396, A100536, Q(n)=n*(2*n^2+9*n+9)/2 , new.
Triangle Checkbernou1 with the same denominator A080326 for every row is
1/1
(2 -3)/2
(6 -15 +10)/6
(6 -21 +25 -10)/6
(30 -135 +230 -175 +49)/30
(30 -165 +365 -405 +224 -49)/30;
Hence for numerator: 1, 2-3, 16-15, 31-31, 309-310, 619-619, 8171-8166.
Absolute sum: 1, 5, 31, 62, 619, 1238, 17337. Reduced division by A080326:
1, 5/2, 31/6, 31/3, 619/30, 619/15, 5779/70, = A172030(n+1)/A172031(n+1).

Crossrefs

Cf. A028246 (Worpitzky), A085737/A085738 (Conway-Sloane), A051714/A051715 (Akiyama-Tanigawa), A192456/A191302 for other triangles that lead to the Bernoulli numbers.

Formula

CB(0,x) = 1,
CB(1,x) = 1 - 3*x/2,
CB(n,x) = (1-x)*CB(n-1,x) + B(n)*x^n , n > 1.

A230262 Numerators of Akiyama-Tanigawa algorithm applied to harmonic numbers, written by antidiagonals.

Original entry on oeis.org

1, 3, -1, 11, -2, 1, 25, -3, 1, 0, 137, -4, 3, 1, -1, 49, -5, 2, 1, -1, 0, 363, -6, 5, 2, -3, -1, 1, 761, -7, 3, 5, -1, -1, 1, 0, 7129, -8, 7, 5, 0, -4, 1, 1, -1, 7381, -9, 4, 7, 1, -1, -1, 1, -1, 0, 83711, -10, 9, 28, 49, -29, -5, 8, 1, -5, 5
Offset: 0

Views

Author

Paul Curtz, Nov 09 2013

Keywords

Comments

Leading column gives the Bernoulli numbers: A027641(n)/A027642(n). In A051714, A164555 must be written instead of A027641.

Examples

			Numerators of
1,    3/2, 11/6, 25/12,...
-1/2, -2/3, -3/4,  -4/5,...
1/6,   1/6, 3/20,  2/15,... =A026741(n+1)/A045896(n+1)
0,    1/30, 1/20,  2/35,... =A194531/A193220.
		

Crossrefs

Programs

  • Mathematica
    t[1, k_] := HarmonicNumber[k]; t[n_, k_] := t[n, k] = k*(t[n-1, k] - t[n-1, k+1]); Table[t[n-k+1, k] // Numerator, {n, 1, 12}, {k, n, 1, -1}] // Flatten (* Jean-François Alcover, Nov 15 2013 *)

Extensions

More terms from Jean-François Alcover, Nov 15 2013
Previous Showing 11-18 of 18 results.