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 11-20 of 20 results.

A015007 q-factorial numbers for q=8.

Original entry on oeis.org

1, 1, 9, 657, 384345, 1799118945, 67375205371305, 20185139902805378865, 48378633136349277767794425, 927610024989668734297857360967425, 142287668466497494704440569679875994730825, 174605966461872393482359052970987514818406771638225
Offset: 0

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Author

Keywords

Crossrefs

Programs

  • Magma
    [n le 1 select 1 else (8^n-1)*Self(n-1)/7: n in [1..15]]; // Vincenzo Librandi, Oct 26 2012
  • Mathematica
    RecurrenceTable[{a[1]==1, a[n]==((8^n - 1) * a[n-1])/7}, a, {n, 15}] (* Vincenzo Librandi, Oct 26 2012 *)
    Table[QFactorial[n, 8], {n, 15}] (* Bruno Berselli, Aug 14 2013 *)

Formula

a(n) = Product_{k=1..n} ((q^k - 1) / (q - 1)), with q=8.
a(0) = 1, a(n) = (8^n-1)*a(n-1)/7. - Vincenzo Librandi, Oct 26 2012
From Amiram Eldar, Jul 05 2025: (Start)
a(n) = Product_{k=1..n} A023001(k).
a(n) ~ c * 8^(n*(n+1)/2)/7^n, where c = A132036. (End)

Extensions

a(0)=1 prepended by Alois P. Heinz, Sep 08 2021

A015008 q-factorial numbers for q=9.

Original entry on oeis.org

1, 1, 10, 910, 746200, 5507702200, 365876657146000, 218747042884536166000, 1177042838234827583459440000, 57001313848230245122464621625840000, 24843911488189148287648216529610193612000000, 97453533413342456299179976631323547842824103012000000
Offset: 0

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Author

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Crossrefs

Programs

  • Magma
    [n le 1 select 1 else (9^n - 1)*Self(n-1)/8: n in [1..15]]; // Vincenzo Librandi, Oct 26 2012
  • Mathematica
    RecurrenceTable[{a[1]==1, a[n]==((9^n - 1) * a[n-1])/8}, a, {n, 15}] (* Vincenzo Librandi, Oct 26 2012 *)
    Table[QFactorial[n, 9], {n, 15}] (* Bruno Berselli, Aug 14 2013 *)

Formula

a(n) = Product_{k=1..n} (9^k - 1) / (9 - 1).
a(0) = 1, a(n) = (9^n - 1)*a(n-1)/8. - Vincenzo Librandi, Oct 26 2012
From Amiram Eldar, Jul 05 2025: (Start)
a(n) = Product_{k=1..n} A002452(k).
a(n) ~ c * 3^(n*(n+1))/8^n, where c = A132037. (End)

Extensions

a(0)=1 prepended by Alois P. Heinz, Sep 08 2021

A015009 q-factorial numbers for q=10.

Original entry on oeis.org

1, 1, 11, 1221, 1356531, 15072415941, 1674711207620451, 1860790044610366931061, 20675444733360738721748118771, 2297271634742810443154153338805764581, 2552524038347870310755413660544832496799359491, 28361378203581611893021499527080870668821235178133404501
Offset: 0

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Author

Keywords

Crossrefs

Programs

  • Magma
    [n le 1 select 1 else (10^n-1)*Self(n-1)/9: n in [1..15]]; // Vincenzo Librandi, Oct 26 2012
  • Mathematica
    RecurrenceTable[{a[1]==1, a[n]==((10^n-1) * a[n-1])/9}, a, {n, 15}] (* Vincenzo Librandi, Oct 26 2012 *)
    Table[QFactorial[n, 10], {n, 15}] (* Bruno Berselli, Aug 14 2013 *)

Formula

a(n) = Product_{k=1..n} (q^k - 1)/(q - 1) with q=10.
a(0) = 1, a(n) = (10^n - 1)*a(n-1)/9. - Vincenzo Librandi, Oct 26 2012
From Amiram Eldar, Jul 05 2025: (Start)
a(n) = Product_{k=1..n} A002275(k).
a(n) ~ c * 10^(n*(n+1)/2)/9^n, where c = A132038. (End)

Extensions

a(0)=1 prepended by Alois P. Heinz, Sep 08 2021

A015011 q-factorial numbers for q=11.

Original entry on oeis.org

1, 1, 12, 1596, 2336544, 37630041120, 6666387564654720, 12990902775831251994240, 278471536921607824648305285120, 65662131721505488121539650946349537280, 170310659060181679663863033233125976844488908800, 4859161865915056755501262525796512204608930674134393036800
Offset: 0

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Author

Keywords

Crossrefs

Programs

  • Magma
    [n le 1 select 1 else (11^n-1)*Self(n-1)/10: n in [1..15]]; // Vincenzo Librandi, Oct 26 2012
  • Mathematica
    RecurrenceTable[{a[1]==1, a[n]==((11^n - 1) * a[n-1])/10}, a, {n, 15}] (* Vincenzo Librandi, Oct 26 2012 *)
    Table[QFactorial[n, 11], {n, 11}] (* Bruno Berselli, Aug 14 2013 *)

Formula

a(n) = Product_{k=1..n} (11^k - 1) / (11 - 1).
a(0) = 1, a(n) = (11^n - 1)*a(n-1)/10. - Vincenzo Librandi, Oct 26 2012
From Amiram Eldar, Jul 05 2025: (Start)
a(n) = Product_{k=1..n} A016123(k-1).
a(n) ~ c * 11^(n*(n+1)/2)/10^n, where c = A132267. (End)

Extensions

a(0)=1 prepended by Alois P. Heinz, Sep 08 2021

A015005 q-factorial numbers for q=6.

Original entry on oeis.org

1, 1, 7, 301, 77959, 121226245, 1131162092095, 63330372050122765, 21274128570193389587095, 42878835824239014254983869205, 518543838148941095553869851505328175, 37625235473766496167083515195884075739704925, 16380389585902052954270520869620904155598347770499975
Offset: 0

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Author

Keywords

Crossrefs

Programs

  • Magma
    [n le 1 select 1 else (6^n-1)*Self(n-1)/5: n in [1..15]]; // Vincenzo Librandi, Oct 25 2012
  • Mathematica
    RecurrenceTable[{a[1]==1, a[n]==((6^n - 1) * a[n-1])/5}, a, {n, 15}] (* Vincenzo Librandi, Oct 25 2012 *)
    Table[QFactorial[n, 6], {n, 15}] (* Bruno Berselli, Aug 14 2013 *)

Formula

a(n) = Product_{k=1..n} (6^k-1)/(6-1).
a(0) = 1, a(n) = (6^n-1)*a(n-1)/5. - Vincenzo Librandi, Oct 25 2012
From Amiram Eldar, Jul 05 2025: (Start)
a(n) = Product_{k=1..n} A003464(k).
a(n) ~ c * 6^(n*(n+1)/2)/5^n, where c = A132034. (End)

Extensions

a(0)=1 prepended by Alois P. Heinz, Sep 08 2021

A069779 q-factorial numbers 4!_q.

Original entry on oeis.org

1, 24, 315, 2080, 8925, 29016, 77959, 182400, 384345, 746200, 1356531, 2336544, 3847285, 6097560, 9352575, 13943296, 20276529, 28845720, 40242475, 55168800, 74450061, 99048664, 130078455, 168819840, 216735625, 275487576, 346953699, 433246240, 536730405, 660043800
Offset: 0

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Crossrefs

Programs

  • Mathematica
    Table[QFactorial[4, n], {n, 0, 29}] (* Arkadiusz Wesolowski, Nov 01 2012 *)
    LinearRecurrence[{7,-21,35,-35,21,-7,1},{1,24,315,2080,8925,29016,77959},30] (* Harvey P. Dale, Aug 30 2020 *)

Formula

a(n) = (n + 1)*(n^2 + n + 1)*(n^3 + n^2 + n + 1).
G.f.: (1 + 17*x + 8*x^2*(21 + 43*x) + 5*x^4*(35 + 3*x))/(1 - x)^7. - Arkadiusz Wesolowski, Nov 01 2012

A218503 q-factorial numbers 5!_q.

Original entry on oeis.org

1, 120, 9765, 251680, 3043425, 22661496, 121226245, 510902400, 1799118945, 5507702200, 15072415941, 37630041120, 87029433985, 188664603960, 386925380325, 756298318336, 1417430759745, 2559798038520, 4472991338725, 7589075296800, 12538953723681
Offset: 0

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Author

Arkadiusz Wesolowski, Oct 31 2012

Keywords

Crossrefs

Programs

  • Mathematica
    Table[QFactorial[5, n], {n, 0, 20}]
    Join[{1},With[{f=Times@@Table[Total[n^Range[0,i]],{i,4}]},Table[f,{n,20}]]] (* or *) LinearRecurrence[{11,-55,165,-330,462,-462,330,-165,55,-11,1},{1,120,9765,251680,3043425,22661496,121226245,510902400,1799118945,5507702200,15072415941},30] (* Harvey P. Dale, Sep 04 2017 *)

Formula

a(n) = (n + 1)*(n^2 + n + 1)*(n^3 + n^2 + n + 1)*(n^4 + n^3 + n^2 + n + 1).
G.f.: (1 + x*(109 + x*(8500 + x*(150700 + x*(792550 + x*(1454134 + x*(978436 + 5*x*(45788 + x*(3053 + 33*x)))))))))/(1 - x)^11.

A347611 a(n) is the n-th n-factorial number: a(n) = n!_n.

Original entry on oeis.org

1, 1, 3, 52, 8925, 22661496, 1131162092095, 1375009641495014400, 48378633136349277767794425, 57001313848230245122464621625840000, 2552524038347870310755413660544832496799359491, 4859161865915056755501262525796512204608930674134393036800
Offset: 0

Views

Author

Alois P. Heinz, Sep 08 2021

Keywords

Crossrefs

Main diagonal of A069777.
Cf. A366355.

Programs

  • Maple
    b:= proc(n, k) option remember; `if`(n<2, 1,
          b(n-1, k)*(k^n-1)/(k-1))
        end:
    a:= n-> b(n$2):
    seq(a(n), n=0..12);
  • Mathematica
    Array[QFactorial[#, #] &, 12, 0] (* Michael De Vlieger, Sep 09 2021 *)
  • PARI
    a(n) = if (n<=1, 1, prod(k=1, n, (n^k-1)/(n-1))); \\ Michel Marcus, Sep 09 2021
    
  • Python
    from math import prod
    def a(n):
        return 1 if n <= 1 else prod((n**k - 1)//(n - 1) for k in range(1, n+1))
    print([a(n) for n in range(12)]) # Michael S. Branicky, Sep 09 2021

Formula

a(n) = Product_{j=1..n} (n^j-1)/(n-1) for n > 1, a(0) = a(1) = 1.
a(n) = A069777(n,n).
a(n) ~ exp(1) * n^(n*(n-1)/2). - Vaclav Kotesovec, Jun 09 2025

A276823 a(n) = 3 * [3*n]_2! / ([2*n+1]_2! * [n+1]_2!), where [n]_q! is the q-factorial.

Original entry on oeis.org

1, 9, 1241, 2634489, 87807053113, 46414431022602681, 390913823614809035461305, 52571422826552549403006580802745, 113007269646365312407427675894837602068665, 3884802624238339577626451297006421856376970743148729
Offset: 1

Views

Author

Vladimir Reshetnikov, Sep 18 2016

Keywords

Crossrefs

Programs

  • Maple
    a:= n-> 3*mul((2^j-1), j=1..3*n)/
             (mul((2^j-1), j=1..2*n+1)*
              mul((2^j-1), j=1..n+1)):
    seq(a(n), n=1..12);  # Alois P. Heinz, Sep 20 2016
  • Mathematica
    Table[3 QFactorial[3 n, 2]/(QFactorial[2 n + 1, 2] QFactorial[n + 1, 2]), {n, 10}] (* or *)
    Table[3 QBinomial[3 n, 2 n + 1, 2]/(1 - 3 * 2^n + 2^(2 n + 1)), {n, 10}]

Formula

a(n) ~ c * 2^((n-2)*(2*n+1)), where c = 3/QPochhammer(1/2, 1/2) = 3*A065446 = 3/A048651. - Vaclav Kotesovec, Sep 20 2016

A320354 Square array A(n,k), n >= 0, k >= 1, read by antidiagonals: A(n,k) = Product_{j=1..n} (k^j - 1).

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 2, 3, 0, 1, 3, 16, 21, 0, 1, 4, 45, 416, 315, 0, 1, 5, 96, 2835, 33280, 9765, 0, 1, 6, 175, 11904, 722925, 8053760, 615195, 0, 1, 7, 288, 37625, 7428096, 739552275, 5863137280, 78129765, 0, 1, 8, 441, 98496, 48724375, 23205371904, 3028466566125, 12816818094080, 19923090075, 0
Offset: 0

Views

Author

Ilya Gutkovskiy, Oct 11 2018

Keywords

Examples

			Square array begins:
  1,     1,        1,          1,            1,             1,  ...
  0,     1,        2,          3,            4,             5,  ...
  0,     3,       16,         45,           96,           175,  ...
  0,    21,      416,       2835,        11904,         37625,  ...
  0,   315,    33280,     722925,      7428096,      48724375,  ...
  0,  9765,  8053760,  739552275,  23205371904,  378832015625,  ...
		

Crossrefs

Programs

  • Mathematica
    Table[Function[k, Product[k^j - 1, {j, 1, n}]][m - n + 1], {m, 0, 9}, {n, 0, m}] // Flatten
    Table[Function[k, SeriesCoefficient[Sum[k^(i (i + 1)/2) x^i/Product[(1 + k^j x), {j, 0, i}], {i, 0, n}], {x, 0, n}]][m - n + 1], {m, 0, 9}, {n, 0, m}] // Flatten

Formula

G.f. of column k: Sum_{i>=0} k^(i*(i+1)/2)*x^i / Product_{j=0..i} (1 + k^j*x).
For asymptotics of column k see comment from Vaclav Kotesovec in A027880.
Previous Showing 11-20 of 20 results.