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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A002239 9th powers written backwards.

Original entry on oeis.org

0, 1, 215, 38691, 441262, 5213591, 69677001, 70635304, 827712431, 984024783, 1, 1967497532, 2530879515, 37399440601, 48764016602, 57395334483, 63767491786, 794678785811, 863092953891, 977796786223, 215, 185640082497, 2977129627021, 3641662511081, 4220457081462
Offset: 0

Views

Author

Keywords

Crossrefs

Cf. A001017.

Programs

  • Maple
    a:= n-> (s-> parse(cat(s[-i]$i=1..length(s))))(""||(n^9)):
    seq(a(n), n=0..50);  # Alois P. Heinz, Apr 09 2015

A016797 a(n) = (3*n + 2)^9.

Original entry on oeis.org

512, 1953125, 134217728, 2357947691, 20661046784, 118587876497, 512000000000, 1801152661463, 5429503678976, 14507145975869, 35184372088832, 78815638671875, 165216101262848, 327381934393961, 618121839509504, 1119130473102767, 1953125000000000, 3299763591802133
Offset: 0

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Author

Keywords

Crossrefs

Programs

Formula

G.f.: (512 + 1948005*x + 114709518*x^2 + 1103599596*x^3 + 2887100154*x^4 + 2388954618*x^5 + 608260290*x^6 + 37732212*x^7 + 262134*x^8 + x^9)/(1 - x)^10. - Ilya Gutkovskiy, Jun 16 2016
From Amiram Eldar, Mar 31 2022: (Start)
a(n) = A016789(n)^9.
Sum_{n>=0} 1/a(n) = 9841*zeta(9)/19683 - 1618*Pi^9/(55801305*sqrt(3)). (End)

A168372 a(n) = n^5*(n^4 + 1)/2.

Original entry on oeis.org

0, 1, 272, 9963, 131584, 978125, 5042736, 20185207, 67125248, 193739769, 500050000, 1179054371, 2580014592, 5302435333, 10330792304, 19222059375, 34360262656, 59294648177, 99180589968, 161345086939, 256001600000
Offset: 0

Views

Author

N. J. A. Sloane, Dec 11 2009

Keywords

Comments

Number of unoriented rows of length 9 using up to n colors. For a(0)=0, there are no rows using no colors. For a(1)=1, there is one row using that one color for all positions. For a(2)=272, there are 2^9=512 oriented arrangements of two colors. Of these, 2^5=32 are achiral. That leaves (512-32)/2=240 chiral pairs. Adding achiral and chiral, we get 272. - Robert A. Russell, Nov 13 2018

Crossrefs

Row 9 of A277504.
Cf. A001017 (oriented), A000584 (achiral).

Programs

Formula

G.f.: x*(1 + 262*x + 7288*x^2 + 44074*x^3 + 78190*x^4 + 44074*x^5 + 7288*x^6 + 262*x^7 + x^8)/(1 - x)^10. - G. C. Greubel, Jul 19 2016
From Robert A. Russell, Nov 13 2018: (Start)
a(n) = (A001017(n) + A000584(n)) / 2 = (n^9 + n^5) / 2.
G.f.: (Sum_{j=1..9} S2(9,j)*j!*x^j/(1-x)^(j+1) + Sum_{j=1..5} S2(5,j)*j!*x^j/(1-x)^(j+1)) / 2, where S2 is the Stirling subset number A008277.
G.f.: x*Sum_{k=0..8} A145882(9,k) * x^k / (1-x)^10.
E.g.f.: (Sum_{k=1..9} S2(9,k)*x^k + Sum_{k=1..5} S2(5,k)*x^k) * exp(x) / 2, where S2 is the Stirling subset number A008277.
For n>9, a(n) = Sum_{j=1..10} -binomial(j-11,j) * a(n-j). (End)
E.g.f.: x*(2 +270*x +3050*x^2 +7780*x^3 +6952*x^4 +2646*x^5 +462*x^6 + 36*x^7 +x^8)*exp(x)/2. - G. C. Greubel, Nov 15 2018

A198478 a(n) = 9^n * n^9.

Original entry on oeis.org

0, 9, 41472, 14348907, 1719926784, 115330078125, 5355700839936, 193010051319183, 5777633090469888, 150094635296999121, 3486784401000000000, 73994897046174912819, 1457274373159131021312, 26955214582765006137717
Offset: 0

Views

Author

Vincenzo Librandi, Oct 27 2011

Keywords

Crossrefs

Programs

  • Magma
    [9^n*n^9: n in [0..20]]
    
  • Mathematica
    Table[9^n*n^9, {n, 0, 20}] (* G. C. Greubel, May 17 2022 *)
  • SageMath
    [9^n*n^9 for n in (0..20)] # G. C. Greubel, May 17 2022

Formula

G.f.: 9*x*(1 + 4518*x + 1183248*x^2 + 64322586*x^3 + 1024762590*x^4 + 5210129466*x^5 + 7763290128*x^6 + 2401050438*x^7 + 43046721*x^8)/(1 - 9*x)^10. - Colin Barker, Apr 30 2013
a(n) = A001019(n)*A001017(n). - Michel Marcus, May 18 2022

A017169 a(n) = (9*n)^9.

Original entry on oeis.org

0, 387420489, 198359290368, 7625597484987, 101559956668416, 756680642578125, 3904305912313344, 15633814156853823, 51998697814228992, 150094635296999121, 387420489000000000, 913517247483640899
Offset: 0

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Author

Keywords

Comments

a(n) = A155955(n,9) for n > 8. - Reinhard Zumkeller, Jan 31 2009

Programs

  • Magma
    [(9*n)^9: n in [0..20]]; // Vincenzo Librandi, Jul 22 2011
  • Mathematica
    (9*Range[0,20])^9 (* or *) LinearRecurrence[{10,-45,120,-210,252,-210,120,-45,10,-1},{0,387420489,198359290368,7625597484987,101559956668416,756680642578125,3904305912313344,15633814156853823,51998697814228992,150094635296999121},20] (* Harvey P. Dale, Dec 11 2017 *)

Formula

a(n) = 387420489*A001017(n). - R. J. Mathar, Jul 07 2017

A075670 Sum of next n 9th powers.

Original entry on oeis.org

1, 20195, 12292965, 1561991824, 77226633575, 2014634387961, 33098483802475, 383318212734080, 3377498614484589, 23898971839102975, 141290020118952881, 719054471032657200, 3223613105991831475, 12964037775857022869, 47453810583528962775, 159982264435790734336
Offset: 1

Views

Author

Zak Seidov, Sep 24 2002

Keywords

Examples

			a(1) = 1^9 = 1; a(2) = 2^9 + 3^9 = 20195; a(3) = 4^9 + 5^9 + 6^9 = 12292965; a(4) = 7^9 + 8^9 + 9^9 + 10^9 = 1561991824.
		

Crossrefs

Cf. A001017 (9th powers).
Cf. A006003, A072474 (for squares), A075664 - A075671 (3rd to 10th powers), A069876 (n-th powers).

Programs

  • Magma
    [(5*n^19 + 105*n^17 + 666*n^15 + 1530*n^13 + 689*n^11 - 995*n^9 + 304*n^7 + 640*n^5 - 384*n^3)/2560 : n in [1..20]]; // Vincenzo Librandi, Oct 06 2011
  • Mathematica
    i1 := n(n-1)/2+1; i2 := n(n-1)/2+n; s=9; Table[Sum[i^s, {i, i1, i2}], {n, 20}]
    Total[#^9]&/@(Range[First[#]+1,Last[#]]&/@Partition[Accumulate[Range[ 0,15]],2,1]) (* Harvey P. Dale, Oct 05 2011 *)
    With[{nn=20},Total/@TakeList[Range[(nn(nn+1))/2]^9,Range[nn]]] (* Harvey P. Dale, Aug 05 2025 *)

Formula

a(n) = Sum_{i=n(n-1)/2+1..n(n-1)/2+n} i^9.
a(n) = (5n^19 + 105n^17 + 666n^15 + 1530n^13 + 689n^11 - 995n^9 + 304n^7 + 640n^5 - 384n^3)/2560. - Charles R Greathouse IV, Sep 17 2009
G.f.: x*(x^18 +20175*x^17 +11889255*x^16 +1319968434*x^15 +48299442990*x^14 +752964012192*x^13 +5757432094050*x^12 +23468751060270*x^11 +53583908362248*x^10 +70362713036770*x^9 +53583908362248*x^8 +23468751060270*x^7 +5757432094050*x^6+752964012192*x^5 +48299442990*x^4 +1319968434*x^3 +11889255*x^2 +20175*x +1)/(x -1)^20. - Colin Barker, Sep 06 2012

A134010 a(n) = n^(initial digit of n).

Original entry on oeis.org

1, 1, 4, 27, 256, 3125, 46656, 823543, 16777216, 387420489, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 400, 441, 484, 529, 576, 625, 676, 729, 784, 841, 27000, 29791, 32768, 35937, 39304, 42875, 46656, 50653, 54872, 59319, 2560000, 2825761, 3111696
Offset: 0

Views

Author

Reinhard Zumkeller, Oct 02 2007

Keywords

Comments

a(n) = n^A000030(n).

Crossrefs

Programs

  • Mathematica
    a[n_]:= n^First[IntegerDigits[n]];Join[{1},Array[a,42]] (* James C. McMahon, Mar 30 2025 *)

A170790 a(n) = n^9*(n^8 + 1)/2.

Original entry on oeis.org

0, 1, 65792, 64579923, 8590065664, 381470703125, 8463334761216, 116315277170407, 1125899973951488, 8338591043543529, 50000000500000000, 252723515428620731, 1109305555950108672, 4325207964992918653
Offset: 0

Views

Author

N. J. A. Sloane, Dec 11 2009

Keywords

Comments

Number of unoriented rows of length 17 using up to n colors. For a(0)=0, there are no rows using no colors. For a(1)=1, there is one row using that one color for all positions. For a(2)=65792, there are 2^17=131072 oriented arrangements of two colors. Of these, 2^9=512 are achiral. That leaves (131072-512)/2=65280 chiral pairs. Adding achiral and chiral, we get 65792. - Robert A. Russell, Nov 13 2018

Crossrefs

Row 17 of A277504.
Cf. A010805 (oriented), A001017 (achiral).

Programs

  • GAP
    List([0..30], n -> n^9*(n^8+1)/2); # G. C. Greubel, Nov 15 2018
    
  • Magma
    [n^9*(n^8+1)/2: n in [0..20]]; // Vincenzo Librandi, Aug 26 2011
    
  • Mathematica
    Table[(n^9 (n^8+1))/2,{n,0,20}] (* Harvey P. Dale, Oct 03 2016 *)
  • PARI
    for(n=0,30, print1(n^9*(n^8+1)/2, ", ")) \\ G. C. Greubel, Dec 06 2017
    
  • Python
    for n in range(0,20): print(int(n**9*(n**8 + 1)/2), end=', ') # Stefano Spezia, Nov 15 2018
  • Sage
    [n^9*(n^8+1)/2 for n in range(30)] # G. C. Greubel, Nov 15 2018
    

Formula

G.f.: (x + 65774*x^2 + 63395820*x^3 + 7437692410*x^4 + 236676566180*x^5 + 2858646249342*x^6 + 15527826341908*x^7 + 41568611082650*x^8 + 57445191259830*x^9 + 41568611082650*x^10 + 15527826341908*x^11 + 2858646249342*x^12 + 236676566180*x^13 + 7437692410*x^14 + 63395820*x^15 + 65774*x^16 + x^17)/(1-x)^18. - G. C. Greubel, Dec 06 2017
From Robert A. Russell, Nov 13 2018: (Start)
a(n) = (A010805(n) + A001017(n)) / 2 = (n^17 + n^9) / 2.
G.f.: (Sum_{j=1..17} S2(17,j)*j!*x^j/(1-x)^(j+1) + Sum_{j=1..9} S2(9,j)*j!*x^j/(1-x)^(j+1)) / 2, where S2 is the Stirling subset number A008277.
G.f.: x*Sum_{k=0..16} A145882(17,k) * x^k / (1-x)^18.
E.g.f.: (Sum_{k=1..17} S2(17,k)*x^k + Sum_{k=1..9} S2(9,k)*x^k) * exp(x) / 2, where S2 is the Stirling subset number A008277.
For n>17, a(n) = Sum_{j=1..18} -binomial(j-19,j) * a(n-j). (End)

A170791 a(n) = n^9*(n^9 + 1)/2.

Original entry on oeis.org

0, 1, 131328, 193720086, 34359869440, 1907349609375, 50779983373056, 814206819132028, 9007199321849856, 75047317842209805, 500000000500000000, 2779958657925089586, 13311666643022512128, 56227703481280946251
Offset: 0

Views

Author

N. J. A. Sloane, Dec 11 2009

Keywords

Comments

Number of unoriented rows of length 18 using up to n colors. For a(0)=0, there are no rows using no colors. For a(1)=1, there is one row using that one color for all positions. For a(2)=131328, there are 2^18=262144 oriented arrangements of two colors. Of these, 2^9=512 are achiral. That leaves (262144-512)/2=130816 chiral pairs. Adding achiral and chiral, we get 131328. - Robert A. Russell, Nov 13 2018

Crossrefs

Row 18 of A277504.
Cf. A010806 (oriented), A001017 (achiral).

Programs

  • GAP
    List([0..30], n -> n^9*(n^9 + 1)/2); # G. C. Greubel, Nov 15 2018
    
  • Magma
    [n^9*(n^9+1)/2: n in [0..20]]; // Vincenzo Librandi, Aug 26 2011
    
  • Mathematica
    f[n_]:=Module[{n9=n^9},(n9(n9+1))/2]; Array[f,20,0] (* Harvey P. Dale, Nov 24 2012 *)
    Table[n^9*(n^9+1)/2, {n,0,30}] (* G. C. Greubel, Dec 06 2017 *)
  • PARI
    for(n=0,30, print1(n^9*(n^9+1)/2, ", ")) \\ G. C. Greubel, Dec 06 2017
    
  • Python
    for n in range(0,20): print(int(n**9*(n**9 + 1)/2), end=', ') # Stefano Spezia, Nov 15 2018
  • Sage
    [n^9*(1 + n^9)/2 for n in range(30)] # G. C. Greubel, Nov 15 2018
    

Formula

G.f.: (x + 131309*x^2 + 191225025*x^3 + 30701643925*x^4 + 1287510971765*x^5 + 20228672721537*x^6 + 142998536758213*x^7 + 503354983579865*x^8 + 932692830330915*x^9 + 932692827449735*x^10 + 503354984335363*x^11 + 142998537549087*x^12 + 20228672026535*x^13 + 1287511125835*x^14 + 30701669175*x^15 + 191214899*x^16 + 130816*x^17) /(1-x)^19. - G. C. Greubel, Dec 06 2017
From Robert A. Russell, Nov 13 2018: (Start)
a(n) = (A010806(n) + A001017(n)) / 2 = (n^18 + n^9) / 2.
G.f.: (Sum_{j=1..18} S2(18,j)*j!*x^j/(1-x)^(j+1) + Sum_{j=1..9} S2(9,j)*j!*x^j/(1-x)^(j+1)) / 2, where S2 is the Stirling subset number A008277.
G.f.: x*Sum_{k=0..17} A145882(18,k) * x^k / (1-x)^19.
E.g.f.: (Sum_{k=1..18} S2(18,k)*x^k + Sum_{k=1..9} S2(9,k)*x^k) * exp(x) / 2, where S2 is the Stirling subset number A008277.
For n>18, a(n) = Sum_{j=1..19} -binomial(j-20,j) * a(n-j). (End)

A269792 a(n) = 5*n^4.

Original entry on oeis.org

0, 5, 80, 405, 1280, 3125, 6480, 12005, 20480, 32805, 50000, 73205, 103680, 142805, 192080, 253125, 327680, 417605, 524880, 651605, 800000, 972405, 1171280, 1399205, 1658880, 1953125, 2284880, 2657205, 3073280, 3536405, 4050000, 4617605, 5242880, 5929605
Offset: 0

Views

Author

Ilya Gutkovskiy, Mar 31 2016

Keywords

Comments

More generally, the ordinary generating function for the sequences of the form k*n^m, is k*Sum_{j>=1}x^j*j^m (when abs(x)<1).
More generally, the ordinary generating function for the values of quartic polynomial p*n^4 + q*n^3 + k*n^2 + m*n + r, is (r + (p + q + k + m - 4*r)*x + (11*p + 3*q - k - 3*m + 6*r)*x^2 + (11*p - 3*q - k + 3*m - 4*r)*x^3 + (p - q + k - m + r)*x^4)/(1 - x)^5.

Crossrefs

Cf. similar sequences of the form k*n^m, for k = 1...5, m = 1...10: A001477(k = 1, m = 1), A005843 (k = 2, m = 1), A008585 (k = 3, m = 1), A008586 (k = 4, m = 1), A008587 (k = 5, m = 1), A000290 (k = 1, m = 2), A001105 (k = 2, m = 2), A033428 (k = 3, m = 2), A016742 (k = 4, m = 2), A033429 (k = 5, m = 2), A000578 (k = 1, m = 3), A033431 (k = 2, m = 3), A117642 (k = 3, m = 3), A033430 (k = 4, m = 3), A244725 (k = 5, m = 3), A000583 (k = 1, m = 4), A244730 (k = 2, m = 4), A219056 (k = 3, m = 4), A141046 (k = 4, m = 4), this sequence(k = 5, m = 4), A000584 (k = 1, m = 5), A001014 (k = 1, m = 6), A106318 (k = 2, m = 6), A001015 (k = 1, m = 7), A001016 (k = 1, m = 8), A001017 (k = 1, m = 9), A008454 (k = 1, m = 10).

Programs

  • Maple
    A269792:=n->5*n^4: seq(A269792(n), n=0..50); # Wesley Ivan Hurt, Apr 28 2017
  • Mathematica
    Table[5 n^4, {n, 0, 33}]
    LinearRecurrence[{5, -10, 10, -5, 1}, {0, 5, 80, 405, 1280}, 34]
  • PARI
    x='x+O('x^99); concat(0, Vec(5*x*(1+11*x+11*x^2+x^3)/(1-x)^5)) \\ Altug Alkan, Mar 31 2016

Formula

G.f.: 5*x*(1 + 11*x + 11*x^2 + x^3)/(1 - x)^5.
E.g.f.: 5*exp(x)^x*x*(1 + 7*x + 6*x^2 + x^3).
a(n) = 5*a(n-1) - 10*(9n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5).
a(n) = 5*A000583(n) = A008587(n)*A000578(n).
Sum_{n>=1} 1/a(n) = Pi^4/450 = (1/450)*A092425 = 0.216464646742...
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