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 1-4 of 4 results.

A076111 Product of terms in n-th row of A076110.

Original entry on oeis.org

1, 2, 15, 280, 9945, 576576, 49579075, 5925744000, 939536222625, 190787784140800, 48279601331512551, 14894665739501184000, 5502449072258318805625, 2397950328737212204032000
Offset: 0

Views

Author

Amarnath Murthy, Oct 09 2002

Keywords

Crossrefs

Programs

  • GAP
    List([0..15], n-> Product([1..n], j-> j*n+1) ); # G. C. Greubel, Mar 04 2020
  • Magma
    [1] cat [&*[j*n+1: j in [1..n]]: n in [1..15]]; // G. C. Greubel, Mar 04 2020
    
  • Maple
    seq( mul(j*n+1, j=1..n), n=0..15); # G. C. Greubel, Mar 04 2020
  • Mathematica
    Table[Product[j*n+1, {j,n}], {n,0,15}] (* G. C. Greubel, Mar 04 2020 *)
  • Maxima
    A076111(n):=prod(1+n*k,k,1,n)$
    makelist(A076111(n),n,0,30); /* Martin Ettl, Nov 07 2012 */
    
  • PARI
    vector(16, n, my(m=n-1); prod(j=1,m, j*m+1)) \\ G. C. Greubel, Mar 04 2020
    
  • Sage
    [product(j*n+1 for j in (1..n)) for n in (0..15)] # G. C. Greubel, Mar 04 2020
    

Formula

a(n) = Prod_{k=1..n} (1+n*k). - Yalcin Aktar, Jul 14 2009
a(n) = n^n * Pochhammer(n, 1 + 1/n). - G. C. Greubel, Mar 04 2020
a(n) = A092985(n)*(n^2+1). - R. J. Mathar, Mar 30 2023

Extensions

More terms from Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 20 2003

A064808 a(n) is the (n+1)st (n+2)-gonal number.

Original entry on oeis.org

1, 3, 9, 22, 45, 81, 133, 204, 297, 415, 561, 738, 949, 1197, 1485, 1816, 2193, 2619, 3097, 3630, 4221, 4873, 5589, 6372, 7225, 8151, 9153, 10234, 11397, 12645, 13981, 15408, 16929, 18547, 20265, 22086, 24013, 26049, 28197, 30460, 32841, 35343, 37969, 40722
Offset: 0

Views

Author

Floor van Lamoen, Oct 22 2001

Keywords

Comments

Sum of n terms of the arithmetic progression with first term 1 and common difference n-1. - Amarnath Murthy, Aug 04 2005
a(n) is the sum of (n+1)-th row terms of triangle A144693. - Gary W. Adamson, Sep 19 2008
See also A131685(k) = smallest positive number m such that c(i) = m*(i^1 + 1)*(i^2 + 2)* ... *(i^k+ k) / k! takes integral values for all i>=0: For k=2, A131685(k)=1, which implies that this is a well-defined integer sequence. - Alexander R. Povolotsky, Apr 24 2015

Crossrefs

Main diagonal of A057145.
Row sums of A076110.
Cf. A144693. - Gary W. Adamson, Sep 19 2008

Programs

Formula

a(n) = (n+1)*(n^2 + 2)/2.
From Paul Barry, Nov 18 2005: (Start)
a(n) = Sum_{k=0..n} Sum_{j=0..n} (k-(k-1)*C(0, j-k)).
a(n) = A006002(n) - A000096(n-2). (End)
G.f.: (1 - x + 3x^2)/(1 - x)^4. - R. J. Mathar, Jul 07 2009
a(n) = A006003(n+1) - A002378(n). - Rick L. Shepherd, Feb 21 2015
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4). - Wesley Ivan Hurt, Feb 21 2015
a(n) = A057145(n+2,n+1). - R. J. Mathar, Jul 28 2016

A162609 Triangle read by rows in which row n lists n terms, starting with 1, with gaps = n-2 between successive terms.

Original entry on oeis.org

1, 1, 1, 1, 2, 3, 1, 3, 5, 7, 1, 4, 7, 10, 13, 1, 5, 9, 13, 17, 21, 1, 6, 11, 16, 21, 26, 31, 1, 7, 13, 19, 25, 31, 37, 43, 1, 8, 15, 22, 29, 36, 43, 50, 57, 1, 9, 17, 25, 33, 41, 49, 57, 65, 73, 1, 10, 19, 28, 37, 46, 55, 64, 73, 82, 91, 1, 11, 21, 31, 41, 51, 61, 71, 81
Offset: 1

Views

Author

Omar E. Pol, Jul 09 2009

Keywords

Comments

Equals A081493 when first column is removed. - Georg Fischer, Jul 25 2023

Examples

			Triangle begins:
  1;
  1,  1;
  1,  2,  3;
  1,  3,  5,  7;
  1,  4,  7, 10, 13;
  1,  5,  9, 13, 17, 21;
  1,  6, 11, 16, 21, 26, 31;
		

Crossrefs

Cf. A060354 (row sums), A081493 (without first column).

Programs

  • Mathematica
    Table[NestList[#+(n-2)&,1,n-1],{n,20}]//Flatten (* Harvey P. Dale, Oct 23 2017 *)

Formula

T(n,n) = A002061(n-1).
T(n,k) = A076110(n-1,k) = 1+(n-2)*(k-1). - R. J. Mathar, Mar 30 2023

A092985 a(n) is the product of the first n terms of an arithmetic progression with the first term 1 and common difference n.

Original entry on oeis.org

1, 1, 3, 28, 585, 22176, 1339975, 118514880, 14454403425, 2326680294400, 478015854767451, 122087424094272000, 37947924636264267625, 14105590169042424729600, 6178966019176767549393375, 3150334059785191453342744576, 1849556085478041490537172810625
Offset: 0

Views

Author

Amarnath Murthy, Mar 28 2004

Keywords

Comments

We have the triangle (chopped versions of A076110, A162609)
1;
1 3;
1 4 7;
1 5 9 13;
1 6 11 16 21;
1 7 13 19 25 31;
...
Sequence contains the product of the terms of the rows.
a(n) = b(n-1) where b(n) = n^n*Gamma(n+1/n)/Gamma(1/n) and b(0) is limit n->0+ of b(n). - Gerald McGarvey, Nov 10 2007
Product of the entries in the first column of an n X n square array with elements 1..n^2 listed in increasing order by rows. - Wesley Ivan Hurt, Apr 02 2025

Examples

			a(5) = 1*6*11*16*21 = 22176.
		

Crossrefs

Main diagonal of A256268.

Programs

  • GAP
    List([0..20], n-> Product([0..n-1], j-> j*n+1) ); # G. C. Greubel, Mar 04 2020
  • Magma
    [1] cat [ (&*[j*n+1: j in [0..n-1]]): n in [1..20]]; // G. C. Greubel, Mar 04 2020
    
  • Maple
    a:= n-> mul(n*j+1, j=0..n-1):
    seq(a(n), n=0..20);  # Alois P. Heinz, Nov 24 2015
  • Mathematica
    Flatten[{1, Table[n^n * Pochhammer[1/n, n], {n, 1, 20}]}] (* Vaclav Kotesovec, Oct 05 2018 *)
  • PARI
    vector(21, n, my(m=n-1); prod(j=0,m-1, j*m+1)) \\ G. C. Greubel, Mar 04 2020
    
  • Sage
    [product(j*n+1 for j in (0..n-1)) for n in (0..20)] # G. C. Greubel, Mar 04 2020
    

Formula

a(n) = Product_{k=1..n} (1+(k-1)*n) = 1*(1+n)*(1+2n)*...*(n^2-n+1).
a(n) = Sum_{k=0..n} (-1)^(n-k)*Stirling1(n, k)*n^(n-k). - Vladeta Jovovic, Jan 28 2005
a(n) = n! * [x^n] 1/(1 - n*x)^(1/n) for n > 0. - Ilya Gutkovskiy, Oct 05 2018
a(n) ~ sqrt(2*Pi) * n^(2*n - 3/2) / exp(n). - Vaclav Kotesovec, Oct 05 2018

Extensions

More terms from Erich Friedman, Aug 08 2005
Offset corrected by Alois P. Heinz, Nov 24 2015
Showing 1-4 of 4 results.