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.

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A067426 Sixth column of triangle A067425.

Original entry on oeis.org

1, 9, 216, 5184, 124416, 2985984, 71663616, 1719926784, 41278242816, 990677827584, 23776267862016, 570630428688384, 13695130288521216, 328683126924509184, 7888395046188220416, 189321481108517289984
Offset: 0

Views

Author

Wolfdieter Lang, Jan 25 2002

Keywords

Comments

The fifth column of A067425 gives [1, 8, 160, 3200, 64000, 1280000, 25600000, ...].

Crossrefs

Cf. A009968 (powers of 24), A067404 (fourth column), A067425, A067427 (seventh column).

Programs

Formula

a(n) = A067425(n+5, 5).
a(n) = 9*(4*6)^(n-1), n >= 1, a(0)=1.
G.f.: (1-15*x)/(1-24*x).
E.g.f.: (3*exp(24*x) + 5)/8. - Stefano Spezia, Oct 15 2024

A100403 Digital root of 6^n.

Original entry on oeis.org

1, 6, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9
Offset: 0

Views

Author

Cino Hilliard, Dec 31 2004

Keywords

Comments

Also the digital root of k^n for any k == 6 (mod 9). - Timothy L. Tiffin, Dec 02 2023

Examples

			For n=8, the digits of 6^8 = 1679616 sum to 36, whose digits sum to 9. So, a(8) = 9. - _Timothy L. Tiffin_, Dec 01 2023
		

Crossrefs

Programs

  • Mathematica
    PadRight[{1, 6}, 100, 9] (* Timothy L. Tiffin, Dec 03 2023 *)
  • PARI
    a(n) = if( n<2, [1,6][n+1], 9); \\ Joerg Arndt, Dec 03 2023

Formula

From Timothy L. Tiffin, Dec 01 2023: (Start)
a(n) = 9 for n >= 2.
G.f.: (1+5x+3x^2)/(1-x).
a(n) = A100401(n) for n <> 1.
a(n) = A010888(A000400(n)) = A010888(A001024(n)) = A010888(A009968(n)) = A010888(A009977(n)) = A010888(A009986(n)) = A010888(A159991(n)). (End)
E.g.f.: 9*exp(x) - 3*x - 8. - Elmo R. Oliveira, Aug 09 2024
a(n) = A007953(6*a(n-1)) = A010888(6*a(n-1)). - Stefano Spezia, Mar 20 2025

A218727 a(n) = (24^n - 1)/23.

Original entry on oeis.org

0, 1, 25, 601, 14425, 346201, 8308825, 199411801, 4785883225, 114861197401, 2756668737625, 66160049703001, 1587841192872025, 38108188628928601, 914596527094286425, 21950316650262874201, 526807599606308980825, 12643382390551415539801, 303441177373233972955225
Offset: 0

Views

Author

M. F. Hasler, Nov 04 2012

Keywords

Comments

Partial sums of powers of 24 (A009968); q-integers for q=24: diagonal k=1 in triangle A022188.
Partial sums are in A014913. Also, the sequence is related to A014942 by A014942(n) = n*a(n) - Sum_{i=0..n-1} a(i) for n > 0. [Bruno Berselli, Nov 07 2012]

Crossrefs

Programs

Formula

From Vincenzo Librandi, Nov 07 2012: (Start)
G.f.: x/((1-x)*(1-24*x)).
a(n) = floor(24^n/23).
a(n) = 25*a(n-1) - 24*a(n-2). (End)
E.g.f.: exp(x)*(exp(23*x) - 1)/23. - Elmo R. Oliveira, Aug 29 2024

A100685 Powers of factorials A000142.

Original entry on oeis.org

1, 2, 4, 6, 8, 16, 24, 32, 36, 64, 120, 128, 216, 256, 512, 576, 720, 1024, 1296, 2048, 4096, 5040, 7776, 8192, 13824, 14400, 16384, 32768, 40320, 46656, 65536, 131072, 262144, 279936, 331776, 362880, 518400, 524288, 1048576, 1679616, 1728000
Offset: 1

Views

Author

Kyle Schalm and Jonathan Sondow, Dec 08 2004

Keywords

Comments

Subsequence of A001013. Supersequence of A036740 without its first term.
Supersequence also of A046882 and A055209 without their first terms. - Jonathan Sondow and Robert G. Wilson v, Dec 19 2004

Examples

			24 = (4!)^1 and 36 = (3!)^2.
		

Crossrefs

Cf. also A046882 and A055209.
Subsequences: A000079, A000400, A009968.

Programs

  • Mathematica
    With[{ln = Log[10!]}, Table[With[{f = m!}, Table[f^j, {j, 0, Floor[ln/Log[f]]}]], {m, 2, 10}]] //Flatten //Union

Formula

Sum_{n>=1} 1/a(n) = 1 + A331373. - Amiram Eldar, Nov 21 2021

A267144 Octagonal numbers with prime indices.

Original entry on oeis.org

8, 21, 65, 133, 341, 481, 833, 1045, 1541, 2465, 2821, 4033, 4961, 5461, 6533, 8321, 10325, 11041, 13333, 14981, 15841, 18565, 20501, 23585, 28033, 30401, 31621, 34133, 35425, 38081, 48133, 51221, 56033, 57685, 66305, 68101, 73633, 79381, 83333, 89441, 95765
Offset: 1

Views

Author

Ilya Gutkovskiy, Jan 11 2016

Keywords

Crossrefs

Programs

  • Magma
    [NthPrime(n)*(3*NthPrime(n)-2): n in [1..50]]; // Vincenzo Librandi, Jan 12 2016
    
  • Mathematica
    Table[Prime[n] (3 Prime[n] - 2), {n, 1, 45}]
  • PARI
    lista(nn) = forprime(p=2, nn, print1(p*(3*p-2), ", ")); \\ Altug Alkan, Jan 11 2016
    
  • Python
    from sympy import prime
    def a(n): p = prime(n); return p*(3*p-2)
    print([a(n) for n in range(1, 42)]) # Michael S. Branicky, Aug 21 2021

Formula

a(n) = prime(n)*(3*prime(n) - 2) = A000040(n)*(3*A000040(n) - 2).
a(n) = A000567(A000040(n)).
a(n) = sigma_0(24^(prime(n) - 1)) = A000005(A009968(A000040(n) - 1)).

A013774 a(n) = 24^(3*n + 1).

Original entry on oeis.org

24, 331776, 4586471424, 63403380965376, 876488338465357824, 12116574790945106558976, 167499529910025153071284224, 2315513501476187716057433112576, 32009658644406818986777955348250624
Offset: 0

Views

Author

Keywords

Crossrefs

Subsequence of A009968.

Programs

A013910 a(n) = 24^(5*n + 1).

Original entry on oeis.org

24, 191102976, 1521681143169024, 12116574790945106558976, 96479729228174488169059713024, 768231807465763655682670928358014976, 6117141027690268863066571918245810640257024
Offset: 0

Views

Author

Keywords

Crossrefs

Cf. A009968.

Programs

Formula

a(n) = 7962624*a(n-1), a(0)=24, where 7962624 = 24^5. - Vincenzo Librandi, May 29 2011
G.f.: 24/(1 - 7962624*x). - Stefano Spezia, Sep 09 2018
E.g.f.: 24*exp(7962624*x). - Alejandro J. Becerra Jr., May 18 2021

A013911 a(n) = 24^(5*n + 2).

Original entry on oeis.org

576, 4586471424, 36520347436056576, 290797794982682557415424, 2315513501476187716057433112576, 18437563379178327736384102280592359424, 146811384664566452713597726037899455366168576, 1169003855003308785972158379694803112885582691303424
Offset: 0

Views

Author

Keywords

Crossrefs

Cf. A009968.

Programs

Formula

a(n) = 7962624*a(n-1), a(0)=576, where 7962624 = 24^5 and 576=24^2. - Vincenzo Librandi, May 30 2011
E.g.f.: 576*exp(7962624*x). - Alejandro J. Becerra Jr., May 18 2021

A013912 a(n) = 24^(5*n + 3).

Original entry on oeis.org

13824, 110075314176, 876488338465357824, 6979147079584381377970176, 55572324035428505185378394701824, 442501521100279865673218454734216626176, 3523473231949594865126345424909586928788045824, 28056092520079410863331801112675274709253984591282176
Offset: 0

Views

Author

Keywords

Crossrefs

Cf. A009968.

Programs

Formula

a(n) = 7962624*a(n-1), a(0)=13824, where 7962624 = 24^5 and 13824=24^3. - Vincenzo Librandi, May 30 2011
E.g.f.: 13824*exp(7962624*x). - Alejandro J. Becerra Jr., May 18 2021

A156959 Numerator of Euler(n, 1/24).

Original entry on oeis.org

1, -11, -23, 3421, 13777, -3946811, -23818823, 9662765101, 77747254177, -40597653164651, -408311621397623, 260621490978697981, 3145444161956190577, -2372776776728647969691, -33409916827040236064423, 29080297194139431470874061, 467960606621237943982982977
Offset: 0

Views

Author

N. J. A. Sloane, Nov 07 2009

Keywords

Crossrefs

For denominators see A009968.

Programs

  • Mathematica
    Numerator[EulerE[Range[0, 20], 1/24]] (* Vincenzo Librandi, Jul 31 2014 *)
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