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 10 results.

A100936 Symmetric square array, read by antidiagonals, where the inverse binomial transform of row n equals: [C(n,0)*1, C(n,1)*2,..., C(n,k)*A051163(k), ..., C(n,n)*A051163(n)] and where A051162 equals the antidiagonal sums.

Original entry on oeis.org

1, 1, 1, 1, 3, 1, 1, 5, 5, 1, 1, 7, 14, 7, 1, 1, 9, 28, 28, 9, 1, 1, 11, 47, 76, 47, 11, 1, 1, 13, 71, 163, 163, 71, 13, 1, 1, 15, 100, 301, 435, 301, 100, 15, 1, 1, 17, 134, 502, 971, 971, 502, 134, 17, 1, 1, 19, 173, 778, 1909, 2577, 1909, 778, 173, 19, 1, 1, 21, 217, 1141
Offset: 0

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Author

Paul D. Hanna, Nov 23 2004

Keywords

Comments

Antidiagonal sums form A051163. Main diagonal is A100937. Different from A086620.

Examples

			Rows begin:
[1,1,1,1,1,1,1,1,1,...],
[1,3,5,7,9,11,13,15,17,...],
[1,5,14,28,47,71,100,134,...],
[1,7,28,76,163,301,502,778,...],
[1,9,47,163,435,971,1909,3417,...],
[1,11,71,301,971,2577,5917,12167,...],
[1,13,100,502,1909,5917,15678,36744,...],
[1,15,134,778,3417,12167,36744,97272,...],...
Antidiagonal sums form A051163: [1,2,5,12,30,76,194,496,1269,3250,8337,...].
The inverse binomial transform of the rows form the respective rows of the triangle B:
[1*1],
[1*1,1*2],
[1*1,2*2,1*5],
[1*1,3*2,3*5,1*12],
[1*1,4*2,6*5,4*12,1*30],...
where B(n,k) = binomial(n,k)*A051163(k).
		

Crossrefs

Programs

  • PARI
    T(n,k)=if(n==0 || k==0,1, sum(j=0,n,binomial(k,j)*binomial(n,j)*sum(i=0,j,T(j-i,i)));)

Formula

T(n, k) = Sum_{j=0..n} C(k, j)*C(n, j)*A051162(j), with T(0, 0) = 1 and where Sum_{i=0..n} T(n-i, i) = A051162(n).

A152198 Triangle read by rows, A007318 rows repeated.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 2, 1, 1, 3, 3, 1, 1, 3, 3, 1, 1, 4, 6, 4, 1, 1, 4, 6, 4, 1, 1, 5, 10, 10, 5, 1, 1, 5, 10, 10, 5, 1, 1, 6, 15, 20, 15, 6, 1, 1, 6, 15, 20, 15, 6, 1, 1, 7, 21, 35, 35, 21, 7, 1, 1, 7, 21, 35, 35, 21, 7, 1, 1, 8, 28, 56, 70, 56, 28, 8, 1, 1, 8, 28, 56, 70, 56, 28, 8, 1
Offset: 0

Views

Author

Gary W. Adamson, Nov 28 2008

Keywords

Comments

Eigensequence of the triangle = A051163: (1, 2, 5, 12, 30, 76,...)
Another version of A152815. - Philippe Deléham, Dec 13 2008
Row sums : A016116(n); Diagonal sums: A000931(n+5). - Philippe Deléham, Dec 13 2008
Triangle, with zeros omitted, given by (1, 0, -1, 0, 0, 0, 0, 0, 0, 0, ...) DELTA (0, 1, -1, 0, 0, 0, 0, 0, 0, 0, ...) where DELTA is the operator defined in A084938. - Philippe Deléham, Jan 16 2012
Sums along rising diagonals are A134816. - John Molokach, Jul 09 2013

Examples

			The triangle starts
1;
1;
1, 1;
1, 1;
1, 2, 1;
1, 2, 1;
1, 3, 3, 1;
1, 3, 3, 1;
1, 4, 6, 4, 1;
1, 4, 6, 4, 1;
1, 5, 10, 10, 5, 1;
1, 5, 10, 10, 5, 1;
...
Triangle (1,0,-1,0,0,...) DELTA (0,1,-1,0,0,...) begins:
1
1, 0
1, 1, 0
1, 1, 0, 0
1, 2, 1, 0, 0
1, 2, 1, 0, 0, 0
1, 3, 3, 1, 0, 0, 0
1, 3, 3, 1, 0, 0, 0, 0
1, 4, 6, 4, 1, 0, 0, 0, 0
1, 4, 6, 4, 1, 0, 0, 0, 0, 0
1, 5, 10, 10, 5, 1, 0, 0, 0, 0, 0...
		

Crossrefs

Programs

  • Mathematica
    t[n_, k_] := Binomial[ Floor[n/2], k]; Table[t[n, k], {n, 0, 17}, {k, 0, Floor[n/2]}] // Flatten (* Jean-François Alcover, Sep 13 2012 *)

Formula

Triangle read by rows, Pascal's triangle rows repeated.
Equals inverse binomial transform of A133156 unsigned.
G.f. : (1+x)/(1-(1+y)*x^2). - Philippe Deléham, Jan 16 2012
Sum_{k, 0<=k<=n} T(n,k)*x^k = A057077(n), A019590(n+1), A000012(n), A016116(n), A108411(n), A074872(n+1) for x = -2, -1, 0, 1, 2, 4 respectively. - Philippe Deléham, Jan 16 2012
T(n,k) = A065941(n-k, n-2*k) = abs(A108299(n-k, n-2*k)). - Johannes W. Meijer, Sep 05 2013

Extensions

More terms from Philippe Deléham, Dec 14 2008

A027826 Inverse binomial transform of a_0 = 1, a_1, a_2, etc. is a_0, 0, a_1, 0, a_2, 0, etc.

Original entry on oeis.org

1, 1, 2, 4, 9, 21, 50, 120, 290, 706, 1732, 4280, 10644, 26612, 66824, 168384, 425481, 1077529, 2733746, 6945812, 17669149, 44994345, 114682042, 292544200, 746831570, 1907983346, 4877966628, 12479883736, 31951158024, 81858610968, 209865391600, 538408691456
Offset: 0

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Author

Keywords

Comments

The self-convolution equals A051163. - Paul D. Hanna, Nov 23 2004
Equals row sums of triangle A152193. - Gary W. Adamson, Nov 28 2008

Examples

			Array of successive differences (col. 1 is the inverse binomial transform):
1, 1,  2,  4,  9, 21, 50, ...
0, 1,  2,  5, 12, 29, 70, ...
1, 1,  3,  7, 17, 41, ...
0, 2,  4, 10, 24, 59, ...
2, 2,  6, 14, 35, 87, ...
0, 4,  8, 21, 52, ...
4, 4, 13, 31, 79, ...
0, 9, 18, 48, ...
9, 9, 30, ...
...
		

Crossrefs

Cf. A051163.
Cf. A152193. - Gary W. Adamson, Nov 28 2008

Programs

  • Maple
    a:= proc(n) option remember; add(`if`(k=0, 1,
          `if`(k::odd, 0, a(k/2)))*binomial(n, k), k=0..n)
        end:
    seq(a(n), n=0..40);  # Alois P. Heinz, Jul 08 2015
  • Mathematica
    a[n_] := a[n] = Sum[If[k == 0, 1, If[OddQ[k], 0, a[k/2]]]*Binomial[n, k], {k, 0, n}]; Table[a[n], {n, 0, 40}] (* Jean-François Alcover, Jan 20 2017, translated from Maple *)
  • PARI
    a(n)=local(A,m); if(n<0,0,m=1; A=1+O(x); while(m<=n,m*=2; A=subst(A,x,(x/(1-x))^2)/(1-x)); polcoeff(A,n))
    
  • PARI
    a=List();for(n=1,100,listput(a,sum(i=1,n\2,a[i]*binomial(n,2*i),1))) \\ M. F. Hasler, Aug 19 2015

Formula

G.f. A(x) satisfies A(x^2) = A(x/(1+x))/(1+x) and A(x) = A(x^2/(1-x)^2)/(1-x).
The recursive formula A[n+1] = A[n](x^2/(1-x)^2)/(1-x), A[0]=1, yields exactly 2^n terms after n iterations: A(x) - A[n](x) = x^(2^n) + (2^n+1)*x^(2^n+1) + O(x^(2^n+2)). For example, A[4] = (1-x)^3*(1-2*x-x^2)/((1-2*x)(1-4*x+4*x^2-2*x^4)) = A(x) - x^16 - 17*x^17 + O(x^18). - M. F. Hasler, Aug 19 2015
E.g.f.: exp(x) * Sum_{n>=0} a(n) * x^(2*n) / (2*n)!. - Ilya Gutkovskiy, Feb 26 2022
The expansion of exp(Sum_{n >= 1} a(n)*(2*x)^n/n!) = 1 + 2*x + 6*x^2 + 20*x^3 + 74*x^4 + 292*x^5 + 1204*x^6 + ... appears to have integer coefficients. Equivalently, the Gauss congruences a(n*p^k) == a(n*p^(k-1)) (mod p^k) hold for positive integers k and n and all primes p >= 3. - Peter Bala, Jan 11 2023

Extensions

Incorrect g.f. and formulas removed by R. J. Mathar, Oct 02 2012
Incorrect g.f.s removed by Peter Bala, Jul 07 2015

A051164 Sequence is defined by property that (a0,a1,a2,a3,...) = binomial transform of (a0,a0,a0,a1,a1,a1,a2,a2,a2,a3,a3,a3,...).

Original entry on oeis.org

1, 2, 4, 9, 21, 48, 108, 243, 549, 1243, 2819, 6412, 14640, 33549, 77121, 177747, 410565, 949992, 2200978, 5103623, 11839783, 27471189, 63734823, 147831594, 342767586, 794413545, 1840338975, 4261443374, 9863627962, 22822212734, 52789053456, 122073285984
Offset: 0

Views

Author

Keywords

Crossrefs

Programs

  • Maple
    a:= proc(n) option remember; add(`if`(k<3, 1,
          a(iquo(k, 3)))*binomial(n, k), k=0..n)
        end:
    seq(a(n), n=0..40);  # Alois P. Heinz, Jul 08 2015
  • Mathematica
    a[n_] := a[n] = Sum[If[k<3, 1, a[Quotient[k, 3]]]*Binomial[n, k], {k, 0, n}]; Table[a[n], {n, 0, 40}] (* Jean-François Alcover, Feb 18 2017, after Alois P. Heinz *)

Extensions

More terms from Vladeta Jovovic, Jul 26 2002

A051165 Sequence is defined by property that binomial transform of (a0,a1,a2,a3,...) = (a0,a0,a1,a1,a2,a2,a3,a3,...).

Original entry on oeis.org

1, 0, -1, 2, -4, 8, -12, 8, 15, -56, 81, -26, -130, 208, 306, -2060, 4796, -5120, -6140, 43320, -113768, 182720, -111768, -395696, 1725172, -3922016, 5614348, -2289912, -14957416, 56700032, -121684568, 164735504, -47657969, -491084768, 1740799985, -3598600386, 4619098604
Offset: 0

Views

Author

Keywords

Crossrefs

Programs

  • Maple
    a:= proc(n) option remember; add(`if`(k<2, 1,
          a(iquo(k, 2)))*(-1)^(n-k)*binomial(n, k), k=0..n)
        end:
    seq(a(n), n=0..45);  # Alois P. Heinz, Jul 08 2015
  • Mathematica
    a[n_] := a[n] = Sum[If[k<2, 1, a[Quotient[k, 2]]]*(-1)^(n-k)*Binomial[n, k], {k, 0, n}];
    Table[a[n], {n, 0, 45}] (* Jean-François Alcover, Jun 04 2018, from Maple *)

Extensions

More terms from Vladeta Jovovic, Jul 26 2002

A051166 Sequence is defined by property that binomial transform of (a0,a1,a2,a3,...) = (a0,a0,a0,a1,a1,a1,a2,a2,a2,a3,a3,a3,...).

Original entry on oeis.org

1, 0, 0, -1, 3, -6, 10, -15, 21, -29, 45, -90, 224, -609, 1677, -4559, 12135, -31542, 80086, -199035, 485469, -1165105, 2757369, -6446778, 14913052, -34175805, 77672325, -175228740, 392711166, -874901088, 1938704130, -4275110880, 9385473510, -20521355211, 44704157499, -97055415324
Offset: 0

Views

Author

Keywords

Crossrefs

Programs

  • Maple
    a:= proc(n) option remember; add(`if`(k<3, 1,
          a(iquo(k, 3)))*(-1)^(n-k)*binomial(n, k), k=0..n)
        end:
    seq(a(n), n=0..45);  # Alois P. Heinz, Jul 08 2015
  • Mathematica
    a[n_] := a[n] = Sum[If[k<3, 1, a[Quotient[k, 3]]]*(-1)^(n-k)*Binomial[n, k], {k, 0, n}];
    Table[a[n], {n, 0, 45}] (* Jean-François Alcover, Apr 04 2017, after Alois P. Heinz *)

Extensions

More terms from Vladeta Jovovic, Jul 26 2002

A100937 Main diagonal of symmetric square array A100936.

Original entry on oeis.org

1, 3, 14, 76, 435, 2577, 15678, 97272, 612126, 3891890, 24933292, 160663328, 1040074684, 6759228932, 44075916696, 288289595968, 1890894150707, 12434303045721, 81960791460442, 541428229233012, 3583843659376257
Offset: 0

Views

Author

Paul D. Hanna, Nov 23 2004

Keywords

Examples

			a(3) = 76 = 1*1 + 3^2*2 + 3^2*5 + 1*12 = Sum_{k=0..3} C(3,k)^2*A051163(k).
a(4) = 435 = 1*1 + 4^2*2 + 6^2*5 + 4^2*12 + 1*30 = Sum_{k=0..4} C(4,k)^2*A051163(k).
		

Crossrefs

Programs

  • PARI
    
    				

Formula

a(n) = Sum_{k=0..n} C(n, k)^2*A051162(k).

A059864 a(n) = Product_{i=4..n} (prime(i)-5), where prime(i) is i-th prime.

Original entry on oeis.org

1, 1, 1, 2, 12, 96, 1152, 16128, 290304, 6967296, 181149696, 5796790272, 208684449792, 7930009092096, 333060381868032, 15986898329665536, 863292509801938944, 48344380548908580864, 2997351594032332013568
Offset: 1

Views

Author

Labos Elemer, Feb 28 2001

Keywords

Comments

Such products arise in Hardy-Littlewood prime k-tuplet conjectural formulas.

References

  • Steven R. Finch, Mathematical Constants, Cambridge, 2003, pp. 84-94.
  • R. K. Guy, Unsolved Problems in Number Theory, A8, A1
  • G. H. Hardy and E. M. Wright, An Introduction to the Theory of Numbers, 5th ed., Oxford Univ. Press, 1979.
  • G. Polya, Mathematics and Plausible Reasoning, Vol. II, Appendix Princeton UP, 1954

Crossrefs

Programs

  • Magma
    [n le 3 select 1 else (&*[NthPrime(j) -5: j in [4..n]]): n in [1..30]]; // G. C. Greubel, Feb 02 2023
    
  • Mathematica
    Join[{1,1,1},FoldList[Times,Prime[Range[4,20]]-5]] (* Harvey P. Dale, Dec 29 2018 *)
  • PARI
    a(n) = prod(k=4, n, prime(k)-5); \\ Michel Marcus, Dec 12 2017
    
  • SageMath
    def A059864(n): return product(nth_prime(j) -5 for j in range(4,n+1))
    [A059864(n) for n in range(1,31)] # G. C. Greubel, Feb 02 2023

A352901 a(0) = 1; a(n) = Sum_{k=0..floor(n/3)} binomial(n+1,3*k+1) * a(k).

Original entry on oeis.org

1, 2, 3, 6, 15, 36, 80, 172, 369, 796, 1727, 3774, 8322, 18528, 41643, 94460, 216121, 498186, 1155147, 2689626, 6278841, 14676900, 34316598, 80194032, 187195554, 436310190, 1015176726, 2357708258, 5465611759, 12647864454, 29219750157, 67403414568, 155276809533
Offset: 0

Views

Author

Ilya Gutkovskiy, Apr 07 2022

Keywords

Comments

Self-convolution of A351970.

Crossrefs

Programs

  • Mathematica
    a[0] = 1; a[n_] := a[n] = Sum[Binomial[n + 1, 3 k + 1] a[k], {k, 0, Floor[n/3]}]; Table[a[n], {n, 0, 32}]
    nmax = 32; A[] = 1; Do[A[x] = A[x^3/(1 - x)^3]/(1 - x)^2 + O[x]^(nmax + 1) // Normal, nmax + 1]; CoefficientList[A[x], x]

Formula

G.f. A(x) satisfies: A(x) = A(x^3/(1 - x)^3) / (1 - x)^2.
E.g.f.: d/dx ( exp(x) * Sum_{n>=0} a(n) * x^(3*n+1) / (3*n+1)! ).

A352902 a(0) = 1; a(n) = Sum_{k=0..floor(n/4)} binomial(n+1,4*k+1) * a(k).

Original entry on oeis.org

1, 2, 3, 4, 7, 18, 49, 120, 264, 544, 1100, 2256, 4736, 10080, 21456, 45312, 94850, 197412, 410134, 852968, 1778382, 3719364, 7806338, 16451280, 34835184, 74164800, 158854536, 342478432, 743432288, 1625079936, 3576582592, 7922065408, 17648409603
Offset: 0

Views

Author

Ilya Gutkovskiy, Apr 07 2022

Keywords

Comments

Self-convolution of A351971.

Crossrefs

Programs

  • Mathematica
    a[0] = 1; a[n_] := a[n] = Sum[Binomial[n + 1, 4 k + 1] a[k], {k, 0, Floor[n/4]}]; Table[a[n], {n, 0, 32}]
    nmax = 32; A[] = 1; Do[A[x] = A[x^4/(1 - x)^4]/(1 - x)^2 + O[x]^(nmax + 1) // Normal, nmax + 1]; CoefficientList[A[x], x]

Formula

G.f. A(x) satisfies: A(x) = A(x^4/(1 - x)^4) / (1 - x)^2.
E.g.f.: d/dx ( exp(x) * Sum_{n>=0} a(n) * x^(4*n+1) / (4*n+1)! ).
Showing 1-10 of 10 results.