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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A016948 a(n) = (6*n + 3)^4.

Original entry on oeis.org

81, 6561, 50625, 194481, 531441, 1185921, 2313441, 4100625, 6765201, 10556001, 15752961, 22667121, 31640625, 43046721, 57289761, 74805201, 96059601, 121550625, 151807041, 187388721, 228886641, 276922881, 332150625, 395254161, 466948881, 547981281, 639128961
Offset: 0

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Author

Keywords

Crossrefs

Programs

  • Magma
    [(6*n+3)^4: n in [0..50]]; // Vincenzo Librandi, May 05 2011
  • Mathematica
    a[n_] := (6*n + 3)^4; Array[a, 50, 0] (* Amiram Eldar, Mar 30 2022 *)

Formula

From Amiram Eldar, Mar 30 2022: (Start)
a(n) = A016945(n)^4 = A016946(n)^2.
a(n) = 3^4*A016756(n).
Sum_{n>=0} 1/a(n) = Pi^4/7776. (End)

A016960 a(n) = (6*n + 4)^4.

Original entry on oeis.org

256, 10000, 65536, 234256, 614656, 1336336, 2560000, 4477456, 7311616, 11316496, 16777216, 24010000, 33362176, 45212176, 59969536, 78074896, 100000000, 126247696, 157351936, 193877776, 236421376, 285610000, 342102016, 406586896, 479785216, 562448656, 655360000
Offset: 0

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Author

Keywords

Crossrefs

Subsequence of A000583.

Programs

  • Magma
    [(6*n+4)^4: n in [0..40]]; // Vincenzo Librandi, May 06 2011
  • Mathematica
    (6*Range[0,20]+4)^4 (* or *) LinearRecurrence[{5,-10,10,-5,1},{256,10000,65536,234256,614656},30] (* Harvey P. Dale, Sep 23 2013 *)

Formula

a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5). - Harvey P. Dale, Sep 23 2013
G.f.: 16*(16+545*x+1131*x^2+251*x^3+x^4)/(1-x)^5. - Harvey P. Dale, Aug 21 2021
From Amiram Eldar, Mar 31 2022: (Start)
a(n) = A016957(n)^4 = A016958(n)^2.
a(n) = 16*A016792(n).
Sum_{n>=0} 1/a(n) = PolyGamma(3, 2/3)/7776. (End)

A016972 a(n) = (6*n + 5)^4.

Original entry on oeis.org

625, 14641, 83521, 279841, 707281, 1500625, 2825761, 4879681, 7890481, 12117361, 17850625, 25411681, 35153041, 47458321, 62742241, 81450625, 104060401, 131079601, 163047361, 200533921, 244140625, 294499921, 352275361, 418161601, 492884401, 577200625, 671898241
Offset: 0

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Author

Keywords

Crossrefs

Subsequence of A000583.

Programs

Formula

From Chai Wah Wu, Mar 20 2017: (Start)
a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5) for n > 4.
G.f.: (-x^4 - 2396*x^3 - 16566*x^2 - 11516*x - 625)/(x - 1)^5. (End)
From Amiram Eldar, Apr 01 2022: (Start)
a(n) = A016969(n)^4 = A016970(n)^2.
Sum_{n>=0} 1/a(n) = PolyGamma(3, 5/6)/7776. (End)

A024196 a(n) = 2nd elementary symmetric function of the first n+1 odd positive integers.

Original entry on oeis.org

3, 23, 86, 230, 505, 973, 1708, 2796, 4335, 6435, 9218, 12818, 17381, 23065, 30040, 38488, 48603, 60591, 74670, 91070, 110033, 131813, 156676, 184900, 216775, 252603, 292698, 337386, 387005, 441905, 502448, 569008, 641971, 721735, 808710, 903318
Offset: 1

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Author

Keywords

Examples

			a(8) = 8*80+7*79+6*78+5*77+4*76+3*75+2*74+1*73 = 2796. - _Bruno Berselli_, Mar 13 2012
		

Crossrefs

From Johannes W. Meijer, Jun 08 2009: (Start)
Equals third right hand column of A028338 triangle.
Equals third left hand column of A109692 triangle.
Equals third right hand column of A161198 triangle divided by 2^m.
(End)
Cf. A016061.

Programs

  • GAP
    List([1..36], n -> n*(n+1)*(3*n^2+5*n+1)/6); # Muniru A Asiru, Feb 13 2018
  • Maple
    seq(n*(n+1)*(3*n^2+5*n+1)/6,n=1..25); # Muniru A Asiru, Feb 13 2018
  • Mathematica
    f[k_] := 2 k - 1; t[n_] := Table[f[k], {k, 1, n}]
    a[n_] := SymmetricPolynomial[2, t[n]]
    Table[a[n], {n, 2, 50}]  (* A024196 *)
    (* Clark Kimberling, Dec 31 2011 *)
    Table[(n(n+1)(3n^2+5n+1))/6,{n,50}] (* or *) LinearRecurrence[{5,-10,10,-5,1},{3,23,86,230,505},50] (* Harvey P. Dale, Jul 08 2019 *)

Formula

a(n) = n*(n+1)*(3*n^2+5*n+1)/6.
From Bruno Berselli, Mar 13 2012: (Start)
G.f.: x*(3 + 8*x + x^2)/(1 - x)^5.
a(n) = Sum_{i=1..n} (n+1-i)*((n+1)^2-i).
a(n) = n*A016061(n) - Sum_{i=0..n-1} A016061(i). (End)
a(n) - a(n-1) = A099721(n). Partial sums of A099721.- Philippe Deléham, May 07 2012
a(n) = Sum_{i=1..n} ((2*i-1)*Sum_{j=i..n} (2*j+1)) = 1*(3+5+...2*n+1) + 3*(5+7+...+2*n+1) + ... + (2*n-1)*(2*n+1). - J. M. Bergot, Apr 21 2017
a(n) = A028338(n+1, n-1), n >= 1, (third diagonal). See the crossref. below. Wolfdieter Lang, Jul 21 2017
a(n) = (A000583(n+1) - A000447(n+1))/2. - J. M. Bergot, Feb 13 2018

A062075 a(n) = n^4 * 4^n.

Original entry on oeis.org

0, 4, 256, 5184, 65536, 640000, 5308416, 39337984, 268435456, 1719926784, 10485760000, 61408804864, 347892350976, 1916696264704, 10312216477696, 54358179840000, 281474976710656, 1434879854116864, 7213895789838336, 35822363710849024, 175921860444160000, 855336483526017024
Offset: 0

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Author

Jason Earls, Jun 27 2001

Keywords

Crossrefs

Programs

Formula

G.f.: 4*x*(1+4*x)*(1+40*x+16*x^2) / (1-4*x)^5. - Colin Barker, Apr 30 2013
E.g.f.: 4*x*(1 + 28*x + 96*x^2 + 64*x^3)*exp(4*x). - G. C. Greubel, May 10 2022

A092181 Figurate numbers based on the 24-cell (4-D polytope with Schlaefli symbol {3,4,3}).

Original entry on oeis.org

1, 24, 153, 544, 1425, 3096, 5929, 10368, 16929, 26200, 38841, 55584, 77233, 104664, 138825, 180736, 231489, 292248, 364249, 448800, 547281, 661144, 791913, 941184, 1110625, 1301976, 1517049, 1757728, 2025969, 2323800, 2653321, 3016704
Offset: 1

Views

Author

Michael J. Welch (mjw1(AT)ntlworld.com), Mar 31 2004

Keywords

Comments

This is the 4-dimensional regular convex polytope called the 24-cell, hyperdiamond or icositetrachoron.

Examples

			a(3)= 3^2*((3*3^2)-(4*3)+2) = 9*(27-12+2) = 9*17 = 153
		

Crossrefs

Programs

  • Magma
    [n^2*((3*n^2)-(4*n)+2): n in [1..40]]; // Vincenzo Librandi, May 22 2011
    
  • Mathematica
    Table[SeriesCoefficient[x (1 + 19 x + 43 x^2 + 9 x^3)/(1 - x)^5, {x, 0, n}], {n, 32}] (* Michael De Vlieger, Dec 14 2015 *)
    LinearRecurrence[{5,-10,10,-5,1},{1,24,153,544,1425},40] (* Harvey P. Dale, May 25 2022 *)
  • PARI
    a(n) = n^2*(3*n^2-4*n+2); \\ Michel Marcus, Dec 14 2015

Formula

a(n) = n^2*((3*n^2)-(4*n)+2).
a(n) = C(n+3,4) + 19 C(n+2,4) + 43 C(n+1,4) + 9 C(n,4).
a(n) = +5*a(n-1) -10*a(n-2) +10*a(n-3) -5*a(n-4) +a(n-5). G.f.: x*(1+19*x+43*x^2+9*x^3)/(1-x)^5. [R. J. Mathar, Jun 21 2010]
a(n) = Sum_{k = 1..n} (k^3 + k^7)* binomial(n,k)/binomial(n+k,k). Cf. A034262 and A155977. - Peter Bala, Feb 12 2019

A092182 Figurate numbers based on the 600-cell (4-D polytope with Schlaefli symbol {3,3,5}).

Original entry on oeis.org

1, 120, 947, 3652, 9985, 22276, 43435, 76952, 126897, 197920, 295251, 424700, 592657, 806092, 1072555, 1400176, 1797665, 2274312, 2839987, 3505140, 4280801, 5178580, 6210667, 7389832, 8729425, 10243376, 11946195, 13852972, 15979377
Offset: 1

Views

Author

Michael J. Welch (mjw1(AT)ntlworld.com), Mar 31 2004

Keywords

Comments

This is the 4-dimensional regular convex polytope called the 600-cell, hexacosichoron or hypericosahedron.

Examples

			a(3)= 3*((145*3^3)-(280*3^2)+(179*3)-38)/6 = 3*(3915-2520+537-38)/6 = 0.5*1894 = 947
		

Crossrefs

Programs

  • Magma
    [n*((145*n^3)-(280*n^2)+(179*n)-38)/6: n in [1..40]]; // Vincenzo Librandi, May 22 2011
  • Mathematica
    LinearRecurrence[{5,-10,10,-5,1},{1,120,947,3652,9985},30] (* Harvey P. Dale, May 04 2024 *)

Formula

a(n) = n*((145*n^3)-(280*n^2)+(179*n)-38)/6
a(n) = C(n+3,4) + 115 C(n+2,4) + 357 C(n+1,4) + 107 C(n,4)
a(n) = +5*a(n-1) -10*a(n-2) +10*a(n-3) -5*a(n-4) +a(n-5). G.f.: x*(1+115*x+357*x^2+107*x^3)/(1-x)^5. [R. J. Mathar, Jun 21 2010]

A101104 a(1)=1, a(2)=12, a(3)=23, and a(n)=24 for n>=4.

Original entry on oeis.org

1, 12, 23, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24
Offset: 1

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Author

Cecilia Rossiter, Dec 15 2004

Keywords

Comments

Original name: The first summation of row 4 of Euler's triangle - a row that will recursively accumulate to the power of 4.

Crossrefs

For other sequences based upon MagicNKZ(n,k,z):
..... | n = 1 | n = 2 | n = 3 | n = 4 | n = 5 | n = 6 | n = 7
---------------------------------------------------------------------------
z = 0 | A000007 | A019590 | .......MagicNKZ(n,k,0) = A008292(n,k+1) .......
z = 1 | A000012 | A040000 | A101101 | thisSeq | A101100 | ....... | .......
z = 2 | A000027 | A005408 | A008458 | A101103 | A101095 | ....... | .......
z = 3 | A000217 | A000290 | A003215 | A005914 | A101096 | ....... | .......
z = 4 | A000292 | A000330 | A000578 | A005917 | A101098 | ....... | .......
z = 5 | A000332 | A002415 | A000537 | A000583 | A022521 | ....... | A255181
Cf. A101095 for an expanded table and more about MagicNKZ.

Programs

  • Mathematica
    MagicNKZ = Sum[(-1)^j*Binomial[n+1-z, j]*(k-j+1)^n, {j, 0, k+1}];Table[MagicNKZ, {n, 4, 4}, {z, 1, 1}, {k, 0, 34}]
    Join[{1, 12, 23},LinearRecurrence[{1},{24},56]] (* Ray Chandler, Sep 23 2015 *)

Formula

a(k) = MagicNKZ(4,k,1) where MagicNKZ(n,k,z) = Sum_{j=0..k+1} (-1)^j*binomial(n+1-z,j)*(k-j+1)^n (cf. A101095). That is, a(k) = Sum_{j=0..k+1} (-1)^j*binomial(4, j)*(k-j+1)^4.
a(1)=1, a(2)=12, a(3)=23, and a(n)=24 for n>=4. - Joerg Arndt, Nov 30 2014
G.f.: x*(1+11*x+11*x^2+x^3)/(1-x). - Colin Barker, Apr 16 2012

Extensions

New name from Joerg Arndt, Nov 30 2014
Original Formula edited and Crossrefs table added by Danny Rorabaugh, Apr 22 2015

A177342 a(n) = (4*n^3-3*n^2+5*n-3)/3.

Original entry on oeis.org

1, 9, 31, 75, 149, 261, 419, 631, 905, 1249, 1671, 2179, 2781, 3485, 4299, 5231, 6289, 7481, 8815, 10299, 11941, 13749, 15731, 17895, 20249, 22801, 25559, 28531, 31725, 35149, 38811, 42719, 46881, 51305, 55999, 60971, 66229, 71781, 77635
Offset: 1

Views

Author

Bruno Berselli, May 06 2010 - Nov 27 2010

Keywords

Comments

This sequence is related to the fourth powers (A000583) by n^4 = n*a(n) - Sum_{i=1..n-1} a(i) - (n-1), with n>1.
Also, n*a(n) - Sum_{i=1..n-1} a(i) provides the first column of A162624 and the second column of A162622 (or A162623). - Bruno Berselli, revised Dec 14 2012

Crossrefs

First differences: 2*A084849.
Partial sums: A178073.

Programs

  • Magma
    [(4*n^3-3*n^2+5*n-3)/3: n in [1..39]]; // Bruno Berselli, Aug 24 2011
    
  • Magma
    I:=[1,9,31,75]; [n le 4 select I[n] else 4*Self(n-1)-6*Self(n-2)+4*Self(n-3)-Self(n-4): n in [1..50]]; // Vincenzo Librandi, Aug 19 2013
  • Mathematica
    CoefficientList[Series[(1 + 5 x + x^2 + x^3) / (1 - x)^4, {x, 0, 50}], x] (* Vincenzo Librandi, Aug 19 2013 *)
    Table[(4 n^3 - 3 n^2 + 5 n - 3)/3, {n, 1, 40}] (* Bruno Berselli, Feb 17 2015 *)
    LinearRecurrence[{4,-6,4,-1},{1,9,31,75},40] (* Harvey P. Dale, Jul 31 2021 *)
  • PARI
    a(n)=(4*n^3-3*n^2+5*n-3)/3 \\ Charles R Greathouse IV, Jun 23 2011
    

Formula

G.f.: x*(1 + 5*x + x^2 + x^3)/(1 - x)^4.
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4).
a(n) - a(-n) = 2*A004006(2n).
a(n) + a(-n) = -A002522(n).
a(n) = 1 + (n-1)*(4*n^2+n+6)/3 = 2*A174723(n)-1.

Extensions

Formulae added and revised by Bruno Berselli, Feb 17 2015

A266212 Positive integers x such that x^3 = y^4 + z^2 for some positive integers y and z.

Original entry on oeis.org

8, 13, 20, 25, 40, 125, 128, 193, 200, 208, 225, 313, 320, 328, 400, 500, 605, 640, 648, 1000, 1053, 1156, 1521, 1620, 1625, 1681, 1700, 2000, 2025, 2048, 2125, 2465, 2493, 2873, 2920, 3025, 3088, 3185, 3200, 3240, 3328, 3400, 3600, 3656, 3748, 3816, 4225, 4625, 4913, 5000, 5008, 5120, 5248, 6400, 6728, 6760, 6793, 6845, 7225, 8000
Offset: 1

Views

Author

Zhi-Wei Sun, Dec 23 2015

Keywords

Comments

If x^3 = y^4 + z^2, then (a^(4k)*x)^3 = (a^(3k)*y)^4 + (a^(6k)*z)^2 for all a = 1,2,3,... and k = 0,1,2,... So the sequence has infinitely many terms.
Conjecture: For any integer m, there are infinitely many triples (x,y,z) of positive integers with x^4 - y^3 + z^2 = m.
This is stronger than the conjecture in A266152.

Examples

			a(1) = 8 since 8^3 = 4^4 + 16^2.
a(2) = 13 since 13^3 = 3^4 + 46^2.
a(3) = 20 since 20^3 = 4^4 + 88^2.
a(8) = 193 since 193^3 = 6^4 + 2681^2.
a(12) = 313 since 313^3 = 66^4 + 3419^2.
a(20) = 1000 since 1000^3 = 100^4 + 30000^2.
		

Crossrefs

Programs

  • Mathematica
    SQ[n_]:=SQ[n]=n>0&&IntegerQ[Sqrt[n]]
    n=0;Do[Do[If[SQ[x^3-y^4],n=n+1;Print[n," ",x];Goto[aa]],{y,1,x^(3/4)}];Label[aa];Continue,{x,1,8000}]
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