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 50 results. Next

A253637 Second partial sums of ninth powers (A001017).

Original entry on oeis.org

1, 514, 20710, 303050, 2538515, 14851676, 67518444, 254402940, 828707925, 2403012910, 6335265586, 15427298614, 35123831015, 75481410200, 154282348760, 301802764056, 567911055849, 1032378638010, 1819533917950, 3118689197890, 5212124524411, 8512829068724, 13614686274500, 21358351020500, 32916713032125, 49904578722726
Offset: 1

Views

Author

Luciano Ancora, Jan 07 2015

Keywords

Comments

The formula for the second partial sums of m-th powers is: b(n,m) = (n+1)*F(m) - F(m+1), where F(m) are the m-th Faulhaber's formulas.

Crossrefs

Cf. A001017.

Programs

  • GAP
    List([1..30], n-> n*(n+1)*(n+2)*(n^2+n-1)*(n^2+3*n+1)*(6*n^4+24*n^3 +5*n^2-38*n+ 25)/660 ); # G. C. Greubel, Aug 28 2019
  • Magma
    [n*(n+1)*(n+2)*(n^2+n-1)*(n^2+3*n+1)*(6*n^4+24*n^3+5*n^2-38*n+ 25)/660: n in [1..30]]; // G. C. Greubel, Aug 28 2019
    
  • Maple
    seq(n*(n+1)*(n+2)*(n^2+n-1)*(n^2+3*n+1)*(6*n^4+24*n^3+5*n^2-38*n+ 25)/660, n=1..30); # G. C. Greubel, Aug 28 2019
  • Mathematica
    CoefficientList[Series[(1 +502x +14608x^2 +88234x^3 +156190x^4 +88234x^5 +14608x^6 +502x^7 +x^8)/(1-x)^12, {x, 0, 30}], x] (* Vincenzo Librandi, Jan 19 2015 *)
    Nest[Accumulate,Range[30]^9,2] (* Harvey P. Dale, Apr 18 2021 *)
  • PARI
    a(n) = (6*n^11 + 66*n^10 + 275*n^9 + 495*n^8 + 198*n^7 - 462*n^6 - 330*n^5 + 330*n^4 + 231*n^3 - 99*n^2 - 50*n)/660; \\ Michel Marcus, Jan 08 2015
    
  • Sage
    [n*(n+1)*(n+2)*(n^2+n-1)*(n^2+3*n+1)*(6*n^4+24*n^3+5*n^2-38*n+ 25)/660 for n in (1..30)] # G. C. Greubel, Aug 28 2019
    

Formula

a(n) = n*(n+1)*(n+2)*(n^2+n-1)*(n^2+3*n+1)*(6*n^4 + 24*n^3 + 5*n^2 - 38*n + 25)/660.
a(n) = 2*a(n-1) - a(n-2) + n^9.
G.f.: x*(1 + 502*x + 14608*x^2 + 88234*x^3 + 156190*x^4 + 88234*x^5 + 14608*x^6 + 502*x^7 + x^8)/(1-x)^12. - Vincenzo Librandi, Jan 19 2015

A254643 Third partial sums of ninth powers (A001017).

Original entry on oeis.org

1, 515, 21225, 324275, 2862790, 17714466, 85232910, 339635850, 1168343775, 3571356685, 9906622271, 25333920885, 60457751900, 135939162100, 290221510860, 592024274916, 1159935330765, 2192313968775, 4011847886725, 7130537084615
Offset: 1

Views

Author

Luciano Ancora, Feb 05 2015

Keywords

Examples

			First differences:   1, 511, 19171, 242461, 1690981, ... (A022525)
------------------------------------------------------------------------
The ninth powers:    1, 512, 19683, 262144, 1953125, ... (A001017)
------------------------------------------------------------------------
First partial sums:  1, 513, 20196, 282340, 2235465, ... (A007487)
Second partial sums: 1, 514, 20710, 303050, 2538515, ... (A253637)
Third partial sums:  1, 515, 21225, 324275, 2862790, ... (this sequence)
		

Crossrefs

Programs

  • GAP
    List([1..30], n-> Binomial(n+3,4)*(2*n^8 +24*n^7 +98*n^6 +126*n^5 -97*n^4 -203*n^3 +127*n^2 +84*n -50)/110); # G. C. Greubel, Aug 28 2019
  • Magma
    [Binomial(n+3,4)*(2*n^8 +24*n^7 +98*n^6 +126*n^5 -97*n^4 -203*n^3 +127*n^2 +84*n -50)/110: n in [1..30]]; // G. C. Greubel, Aug 28 2019
    
  • Maple
    seq(binomial(n+3,4)*(2*n^8 +24*n^7 +98*n^6 +126*n^5 -97*n^4 -203*n^3 +127*n^2 +84*n -50)/110, n=1..30); # G. C. Greubel, Aug 28 2019
  • Mathematica
    Table[n(1+n)(2+n)(3+n)(-50 +84n +127n^2 -204n^3 -97n^4 +126n^5 +98n^6 +24n^7 +2n^8)/2640, {n, 20}] (* or *)
    CoefficientList[Series[(1 +502x +14608x^2 +88234x^3 +156190x^4 +88234x^5 +14608x^6 +502x^7 +x^8)/(1-x)^13, {x, 0, 19}], x] (* Ancora *)
    Accumulate[Accumulate[Accumulate[Range[10]^9]]] (* Alonso del Arte, Feb 09 2015 *)
  • PARI
    vector(30, n, m=n+3; binomial(m,4)*(2*(n*m)^4 -10*(n*m)^3 +11*(n*m)^2 +28*(n*m) -50)/110) \\ G. C. Greubel, Aug 28 2019
    
  • Sage
    [binomial(n+3,4)*(2*n^8 +24*n^7 +98*n^6 +126*n^5 -97*n^4 -203*n^3 +127*n^2 +84*n -50)/110 for n in (1..30)] # G. C. Greubel, Aug 28 2019
    

Formula

G.f.: x*(1 +502*x +14608*x^2 +88234*x^3 +156190*x^4 +88234*x^5 +14608*x^6 +502*x^7 +x^8)/(1-x)^13.
a(n) = n*(1+n)*(2+n)*(3+n)*(-50 +84*n +127*n^2 -204*n^3 -97*n^4 +126*n^5 +98*n^6 +24*n^7 +2*n^8)/2640.
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) + n^9.

Extensions

Edited by Alonso del Arte and Bruno Berselli, Feb 10 2015

A255179 Second differences of ninth powers (A001017).

Original entry on oeis.org

1, 510, 18660, 223290, 1448520, 6433590, 22151340, 63588210, 159338640, 359376750, 745368180, 1443884970, 2642886360, 4611828390, 7725765180, 12493804770, 19592282400, 29903014110, 44556993540, 64983894810, 92967744360, 130709124630, 180894272460
Offset: 0

Views

Author

Luciano Ancora, Feb 21 2015

Keywords

Examples

			Second differences:  1, 510, 18660, 223290, 1448520, ... (this sequence)
First differences:   1, 511, 19171, 242461, 1690981, ... (A022525)
------------------------------------------------------------------------
The ninth powers:    1, 512, 19683, 262144, 1953125, ... (A001017)
------------------------------------------------------------------------
First partial sums:  1, 513, 20196, 282340, 2235465, ... (A007487)
Second partial sums: 1, 514, 20710, 303050, 2538515, ... (A253637)
Third partial sums:  1, 515, 21225, 324275, 2862790, ... (A254643)
		

Crossrefs

Programs

  • Magma
    [1] cat [6*n*(3+28*n^2+42*n^4+12*n^6): n in [1..30]]; // Vincenzo Librandi, Mar 12 2015
  • Mathematica
    Join[{1}, Table[6 n (3 + 28 n^2 + 42 n^4 + 12 n^6), {n, 1, 30}]]
    Join[{1},Differences[Range[0,30]^9,2]] (* or *) LinearRecurrence[{8,-28,56,-70,56,-28,8,-1},{1,510,18660,223290,1448520,6433590,22151340,63588210,159338640},30] (* Harvey P. Dale, Jan 26 2019 *)

Formula

G.f.: (1 + 502*x + 14608*x^2 + 88234*x^3 + 156190*x^4 + 88234*x^5 + 14608*x^6 + 502*x^7 + x^8)/(1 - x)^8.
a(n) = 6*n*(3 + 28*n^2 + 42*n^4 + 12*n^6) for n>0, a(0)=1.

Extensions

Corrected g.f. by Bruno Berselli, Feb 25 2015
Offset changed by Bruno Berselli, Mar 20 2015

A238170 Integer part of square root of A001017: a(n) = floor(n^(9/2)).

Original entry on oeis.org

0, 1, 22, 140, 512, 1397, 3174, 6352, 11585, 19683, 31622, 48558, 71831, 102978, 143739, 196069, 262144, 344365, 445375, 568056, 715541, 891223, 1098758, 1342070, 1625363, 1953125, 2330129, 2761448, 3252453, 3808824, 4436552, 5141947, 5931641, 6812597, 7792110
Offset: 0

Views

Author

Philippe Deléham, Feb 21 2014

Keywords

Crossrefs

Integer part of square root of n^k: A000196 (k=1), A000093 (k=3), A155013 (k=5), A155014 (k=7), this sequence (k=9), A155015 (k=11), A155016 (k=13), A155018 (k=15), A155019 (k=17).

Programs

  • Magma
    [Floor(n^(9/2)): n in [0..40]]; // Vincenzo Librandi, Feb 23 2014
    
  • Mathematica
    Table[Floor[n^(9/2)], {n,0,30}] (* G. C. Greubel, Dec 30 2017 *)
  • PARI
    a(n) = floor(n^(9/2)); \\ Joerg Arndt, Feb 23 2014
    
  • Python
    from math import isqrt
    def A238170(n): return isqrt(n**9) # Chai Wah Wu, Jan 27 2023

Formula

a(n) = floor(n^(9/2)).
a(n) = A000196(A001017(n)).
a(n) = floor(n^4*sqrt(n)).

A279642 Exponential transform of the ninth powers A001017.

Original entry on oeis.org

1, 1, 513, 21220, 1130381, 108174916, 8543324917, 800980035472, 88064461381913, 9832425683734288, 1199454069536074601, 158528649288125900224, 21925314644323181005477, 3213026006947537325856832, 497390236613387084643144029, 80481275337746709959509939456
Offset: 0

Views

Author

Alois P. Heinz, Dec 16 2016

Keywords

Crossrefs

Column k=9 of A279636.
Cf. A001017.

Programs

  • Maple
    a:= proc(n) option remember; `if`(n=0, 1,
          add(binomial(n-1, j-1)*j^9*a(n-j), j=1..n))
        end:
    seq(a(n), n=0..25);

Formula

E.g.f.: exp(exp(x)*(x^9+36*x^8+462*x^7+2646*x^6+6951*x^5+7770*x^4 +3025*x^3 +255*x^2+x)).

A255183 Third differences of ninth powers (A001017).

Original entry on oeis.org

1, 509, 18150, 204630, 1225230, 4985070, 15717750, 41436870, 95750430, 200038110, 385991430, 698516790, 1199001390, 1968942030, 3113936790, 4768039590, 7098477630, 10310731710, 14653979430, 20426901270
Offset: 0

Views

Author

Luciano Ancora, Mar 18 2015

Keywords

Examples

			Third differences:   1, 509, 18150, 204630, 1225230, ...  (this sequence)
Second differences:  1, 510, 18660, 223290, 1448520, ...  (A255179)
First differences:   1, 511, 19171, 242461, 1690981, ...  (A022525)
---------------------------------------------------------------------
The ninth powers:    1, 512, 19683, 262144, 1953125, ...  (A001017)
---------------------------------------------------------------------
		

Crossrefs

Programs

  • Magma
    [1,509] cat [6*(84*n^6-252*n^5+630*n^4-840*n^3+756*n^2-378*n+85): n in [2..30]]; // Vincenzo Librandi, Mar 18 2015
  • Mathematica
    Join[{1, 509}, Table[6 (84 n^6 - 252 n^5 + 630 n^4 - 840 n^3 + 756 n^2 - 378 n + 85), {n, 2, 30}]]
    Join[{1,509},Differences[Range[0,20]^9,3]] (* Harvey P. Dale, Apr 24 2015 *)

Formula

G.f.: (1 + 502*x + 14608*x^2 + 88234*x^3 + 156190*x^4 + 88234*x^5 + 14608*x^6 + 502*x^7 + x^8)/(1 - x)^7.
a(n) = 6*(84*n^6 - 252*n^5 + 630*n^4 - 840*n^3 + 756*n^2 - 378*n + 85) for n>1, a(0)=1, a(1)=509.

Extensions

Edited by Bruno Berselli, Mar 20 2015

A268335 Exponentially odd numbers.

Original entry on oeis.org

1, 2, 3, 5, 6, 7, 8, 10, 11, 13, 14, 15, 17, 19, 21, 22, 23, 24, 26, 27, 29, 30, 31, 32, 33, 34, 35, 37, 38, 39, 40, 41, 42, 43, 46, 47, 51, 53, 54, 55, 56, 57, 58, 59, 61, 62, 65, 66, 67, 69, 70, 71, 73, 74, 77, 78, 79, 82, 83, 85, 86, 87, 88, 89, 91, 93, 94, 95, 96, 97
Offset: 1

Views

Author

Vladimir Shevelev, Feb 01 2016

Keywords

Comments

The sequence is formed by 1 and the numbers whose prime power factorization contains only odd exponents.
The density of the sequence is the constant given by A065463.
Except for the first term the same as A002035. - R. J. Mathar, Feb 07 2016
Also numbers k all of whose divisors are bi-unitary divisors (i.e., A286324(k) = A000005(k)). - Amiram Eldar, Dec 19 2018
The term "exponentially odd integers" was apparently coined by Cohen (1960). These numbers were also called "unitarily 2-free", or "2-skew", by Cohen (1961). - Amiram Eldar, Jan 22 2024

Crossrefs

Programs

  • Mathematica
    Select[Range@ 100, AllTrue[Last /@ FactorInteger@ #, OddQ] &] (* Version 10, or *)
    Select[Range@ 100, Times @@ Boole[OddQ /@ Last /@ FactorInteger@ #] == 1 &] (* Michael De Vlieger, Feb 02 2016 *)
  • PARI
    isok(n)=my(f = factor(n)); for (k=1, #f~, if (!(f[k,2] % 2), return (0))); 1; \\ Michel Marcus, Feb 02 2016
    
  • Python
    from itertools import count, islice
    from sympy import factorint
    def A268335_gen(startvalue=1): # generator of terms >= startvalue
        return filter(lambda n:all(e&1 for e in factorint(n).values()),count(max(startvalue,1)))
    A268335_list = list(islice(A268335_gen(),20)) # Chai Wah Wu, Jun 22 2023

Formula

Sum_{a(n)<=x} 1 = C*x + O(sqrt(x)*log x*e^(c*sqrt(log x)/(log(log x))), where c = 4*sqrt(2.4/log 2) = 7.44308... and C = Product_{prime p} (1 - 1/p*(p + 1)) = 0.7044422009991... (A065463).
Sum_{n>=1} 1/a(n)^s = zeta(2*s) * Product_{p prime} (1 + 1/p^s - 1/p^(2*s)), s>1. - Amiram Eldar, Sep 26 2023

A001016 Eighth powers: a(n) = n^8.

Original entry on oeis.org

0, 1, 256, 6561, 65536, 390625, 1679616, 5764801, 16777216, 43046721, 100000000, 214358881, 429981696, 815730721, 1475789056, 2562890625, 4294967296, 6975757441, 11019960576, 16983563041, 25600000000, 37822859361, 54875873536, 78310985281, 110075314176
Offset: 0

Views

Author

Keywords

Comments

Besides the first term, this sequence lists the denominators in Pi^8/9450 = 1 + 1/256 + 1/6561 + 1/65536 + 1/390625 + 1/1679616 + ... - Mohammad K. Azarian, Nov 01 2011, edited by M. F. Hasler, Jul 03 2025
For n > 0, a(n) is the largest number k such that k + n^4 divides k^2 + n^4. - Derek Orr, Oct 01 2014
Fourth powers of squares and squares of 4th powers. Squares composed with themselves twice. - Wesley Ivan Hurt, Apr 01 2016

References

  • Granino A. Korn and Theresa M. Korn, Mathematical Handbook for Scientists and Engineers, McGraw-Hill Book Company, New York (1968), p. 982.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Cf. A000290 (squares), A000583 (fourth powers), A001014 - A001017 (6th - 9th powers), A008454 (10th powers), A010801 (13th powers).
Cf. A000542 (partial sums), A022524 (first differences), A013666 (zeta(8)).
Cf. A003380 - A003390 (sums of 2, ..., 12 eighth powers).

Programs

Formula

Multiplicative with a(p^e) = p^(8e). - David W. Wilson, Aug 01 2001
Totally multiplicative sequence with a(p) = p^8 for primes p. - Jaroslav Krizek, Nov 01 2009
G.f.: -x*(1+x)*(x^6+246*x^5+4047*x^4+11572*x^3+4047*x^2+246*x+1)/(x-1)^9. - R. J. Mathar, Jan 07 2011
a(n) = 8*a(n-1) - 28*a(n-2) + 56*a(n-3) - 70*a(n-4) + 56*a(n-5) - 28*a(n-6) + 8*a(n-7) - a(n-8) + 40320. - Ant King, Sep 24 2013
From Wesley Ivan Hurt, Apr 01 2016: (Start)
a(n) = 9*a(n-1) - 36*a(n-2) + 84*a(n-3) - 126*a(n-4) + 126*a(n-5) - 84*a(n-6) + 36*a(n-7) - 9*a(n-8) + a(n-9) for n > 8.
a(n) = A000290(n)^4 = A000290(A000290(A000290(n))).
a(n) = A000583(n)^2. (End)
From Amiram Eldar, Oct 08 2020: (Start)
Sum_{n>=1} 1/a(n) = zeta(8) = Pi^8/9450 (A013666).
Sum_{n>=1} (-1)^(n+1)/a(n) = 127*zeta(8)/128 = 127*Pi^8/1209600. (End)
E.g.f.: exp(x)*x*(1 + 127*x + 966*x^2 + 1701*x^3 + 1050*x^4 + 266*x^5 + 28*x^6 + x^7). - Stefano Spezia, Jul 29 2022

Extensions

More terms from James Sellers, Sep 19 2000

A008455 11th powers: a(n) = n^11.

Original entry on oeis.org

0, 1, 2048, 177147, 4194304, 48828125, 362797056, 1977326743, 8589934592, 31381059609, 100000000000, 285311670611, 743008370688, 1792160394037, 4049565169664, 8649755859375, 17592186044416, 34271896307633, 64268410079232, 116490258898219, 204800000000000
Offset: 0

Views

Author

Keywords

Crossrefs

Cf. A004813 - A004823 (sums of 2, ..., 12 positive eleventh powers).

Programs

Formula

a(n) = A000584(n)*A001014(n).
Multiplicative with a(p^e) = p^(11*e). - David W. Wilson, Aug 01 2001
Totally multiplicative with a(p) = p^11 for primes p. - Jaroslav Krizek, Nov 01 2009
From Amiram Eldar, Oct 08 2020: (Start)
Sum_{n>=1} 1/a(n) = zeta(11) (A013669).
Sum_{n>=1} (-1)^(n+1)/a(n) = 1023*zeta(11)/1024. (End)

A003391 Numbers that are the sum of 2 positive 9th powers.

Original entry on oeis.org

2, 513, 1024, 19684, 20195, 39366, 262145, 262656, 281827, 524288, 1953126, 1953637, 1972808, 2215269, 3906250, 10077697, 10078208, 10097379, 10339840, 12030821, 20155392, 40353608, 40354119, 40373290, 40615751, 42306732, 50431303, 80707214, 134217729, 134218240, 134237411
Offset: 1

Views

Author

Keywords

Examples

			From _David A. Corneth_, Aug 03 2020: (Start)
4605366718202103 is in the sequence as 4605366718202103 = 8^9 + 55^9.
66540479494556160 is in the sequence as 66540479494556160 = 16^9 + 74^9.
208226326986883072 is in the sequence as 208226326986883072 = 28^9 + 84^9. (End)
		

Crossrefs

Cf. A003380 (8th), A004802 (10th).
Cf. A001017 (ninth powers).
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