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 14 results. Next

A075664 Sum of next n cubes.

Original entry on oeis.org

0, 1, 35, 405, 2584, 11375, 38961, 111475, 278720, 627669, 1300375, 2516921, 4604040, 8030035, 13446629, 21738375, 34080256, 52004105, 77474475, 112974589, 161603000, 227181591, 314375545, 428825915, 577295424, 767828125, 1009923551, 1314725985, 1695229480, 2166499259
Offset: 0

Views

Author

Zak Seidov, Sep 24 2002

Keywords

Examples

			a(1) = 1^3 = 1; a(2) = 2^3 + 3^3 = 35; a(3) = 4^3 + 5^3 + 6^3 = 64 + 125 + 216 = 405.
From _Philippe Deléham_, Mar 09 2014: (Start)
a(1) = 1*2*3/8 = 1;
a(2) = 8*5*7/8 = 35;
a(3) = 27*10*12/8 = 405;
a(4) = 64*17*19/8 = 2584;
a(5) = 125*26*28/8 = 11375; etc. (End)
		

Crossrefs

Cf. A000578 (cubes).
Cf. A006003, A072474 (for squares), A075665 - A075671 (4th to 10th powers), A069876 (n-th powers).

Programs

  • Magma
    [(n^7+4*n^5+3*n^3)/8: n in [1..30]]; // Vincenzo Librandi, Mar 11 2014
    
  • Maple
    A075664:=n->(n^7 + 4n^5 + 3n^3)/8; seq(A075664(n), n=1..30); # Wesley Ivan Hurt, Mar 10 2014
  • Mathematica
    i1 := n(n-1)/2+1; i2 := n(n-1)/2+n; s=3; Table[Sum[i^s, {i, i1, i2}], {n, 20}]
    CoefficientList[Series[(1 + 27 x + 153 x^2 + 268 x^3 + 153 x^4 + 27 x^5 + x^6)/(1 - x)^8, {x, 0, 40}], x](* Vincenzo Librandi, Mar 11 2014 *)
    With[{nn=30},Total/@TakeList[Range[(nn(nn+1))/2]^3,Range[nn]]] (* Requires Mathematica version 11 or later *) (* or *) LinearRecurrence[{8,-28,56,-70,56,-28,8,-1},{1,35,405,2584,11375,38961,111475,278720},30] (* Harvey P. Dale, Jun 05 2021 *)
  • PARI
    a(n)=(n^7+4*n^5+3*n^3)/8 \\ Charles R Greathouse IV, Oct 07 2015
    
  • Python
    def A075664(n): return n*(m:=n**2)*(m*(m+4)+3)>>3 # Chai Wah Wu, Feb 09 2025

Formula

a(n) = Sum_{i=n(n-1)/2+1..n(n-1)/2+n} i^3. [Corrected by Stefano Spezia, Jun 22 2024]
a(n) = (n^7 + 4n^5 + 3n^3)/8. - Charles R Greathouse IV, Sep 17 2009
G.f.: x*(1+27*x+153*x^2+268*x^3+153*x^4+27*x^5+x^6)/(1-x)^8. - Colin Barker, May 25 2012
a(n) = n^3*(n^2 + 1)*(n^2 + 3)/8 = A000578(n)*A002522(n)*A117950(n)/8. - Philippe Deléham, Mar 09 2014
E.g.f.: exp(x)*x*(8 + 132*x + 404*x^2 + 390*x^3 + 144*x^4 + 21*x^5 + x^6)/8. - Stefano Spezia, Jun 22 2024

Extensions

Formula from Charles R Greathouse IV, Sep 17 2009
More terms from Vincenzo Librandi, Mar 11 2014
a(0) added by Chai Wah Wu, Feb 09 2025

A069876 a(n) = (k-n+1)^n + (k-n+2)^n + ... + (k-1)^n + k^n, where k = n(n+1)/2.

Original entry on oeis.org

1, 13, 405, 23058, 2078375, 271739011, 48574262275, 11373936899396, 3377498614484589, 1240006139651007925, 551449374186192949841, 292093390490112799117190, 181694111127303339553250275, 131144830297438122797495823519, 108709456000518111261404495694375
Offset: 1

Views

Author

Amarnath Murthy, Apr 25 2002

Keywords

Comments

Sum of next n n-th powers.

Examples

			a(1) = 1^1 = 1; a(2) = 2^2 + 3^2 = 13; a(3) = 4^3 + 5^3 + 6^3 = 405; a(4) = 7^4 + 8^4 + 9^4 + 10^4 = 23058.
		

Crossrefs

Cf. A072474 (for squares), A075664 - A075671 (3rd to 10th powers).

Programs

  • Mathematica
    i1 := n(n-1)/2+1; i2 := n(n-1)/2+n; Table[Sum[i^n, {i, i1, i2}], {n, 20}]
  • Python
    def A069876(n): return sum(((n*(n+1)>>1)-i)**n for i in range(n)) # Chai Wah Wu, Feb 10 2025

Extensions

More terms from Larry Reeves (larryr(AT)acm.org) and Zak Seidov, Sep 24 2002

A050410 Truncated square pyramid numbers: a(n) = Sum_{k = n..2*n-1} k^2.

Original entry on oeis.org

0, 1, 13, 50, 126, 255, 451, 728, 1100, 1581, 2185, 2926, 3818, 4875, 6111, 7540, 9176, 11033, 13125, 15466, 18070, 20951, 24123, 27600, 31396, 35525, 40001, 44838, 50050, 55651, 61655, 68076, 74928, 82225, 89981, 98210, 106926, 116143
Offset: 0

Views

Author

Klaus Strassburger (strass(AT)ddfi.uni-duesseldorf.de), Dec 22 1999

Keywords

Comments

Starting with offset 1 = binomial transform of [1, 12, 25, 14, 0, 0, 0, ...]. - Gary W. Adamson, Jan 09 2009

Examples

			1^2 + 1;
2^2 + 3^2 = 13;
3^2 + 4^2 + 5^2 = 50; ...
		

Crossrefs

Programs

  • GAP
    List([0..40], n-> n*(7*n-1)*(2*n-1)/6); # G. C. Greubel, Oct 30 2019
  • Magma
    [n*(7*n-1)*(2*n-1)/6: n in [0..40]]; // Vincenzo Librandi, Apr 27 2012
    
  • Maple
    seq(n*(7*n-1)*(2*n-1)/6, n=0..36); # Zerinvary Lajos, Dec 01 2006
  • Mathematica
    Table[Sum[k^2,{k,n,2n-1}],{n,0,40}] (* or *) LinearRecurrence[{4,-6,4, -1}, {0,1,13,50},40] (* Harvey P. Dale, Feb 29 2012 *)
  • PARI
    for(n=1,100,print1(sum(i=0,n-1,(n+i)^2),","))
    
  • PARI
    vector(40, n, (n-1)*(7*n-8)*(2*n-3)/6) \\ G. C. Greubel, Oct 30 2019
    
  • Sage
    [n*(7*n-1)*(2*n-1)/6 for n in (0..40)] # G. C. Greubel, Oct 30 2019
    

Formula

a(n) = n*(7*n-1)*(2*n-1)/6.
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4); a(0)=0, a(1)=1, a(2)=13, a(3)=50. - Harvey P. Dale, Feb 29 2012
G.f.: x*(1 + 9*x + 4*x^2)/(1-x)^4. - Colin Barker, Mar 23 2012
E.g.f.: x*(6 + 33*x + 14*x^2)*exp(x)/6. - G. C. Greubel, Oct 30 2019

A075671 Sum of next n 10th powers.

Original entry on oeis.org

1, 60073, 71280377, 14843001474, 1091618326275, 39736919990851, 870012241054523, 12967387960026452, 143075291905145949, 1240006139651007925, 8817026830146599701, 53151169903167142598, 278615540073819826527, 1295610629596485350799, 5430916505417064431575
Offset: 1

Views

Author

Zak Seidov, Sep 24 2002

Keywords

Examples

			a(1) = 1^10 = 1; a(2) = 2^10 + 3^10 = 60073; a(3) = 4^10 + 5^10 + 6^10 = 71280377; a(4) = 7^10 + 8^10 + 9^10 + 10^10 = 14843001474.
		

Crossrefs

Cf. A008454 (10th powers).
Cf. A072474 (for squares), A075664 - A075670 (3rd to 9th powers), A069876 (n-th powers).

Programs

  • Mathematica
    i1 := n(n-1)/2+1; i2 := n(n-1)/2+n; s=10; Table[Sum[i^s, {i, i1, i2}], {n, 20}]
    With[{nn=20},Total/@TakeList[Range[(nn(nn+1))/2]^10,Range[nn]]] (* Requires Mathematica version 11 or later *) (* Harvey P. Dale, Mar 18 2018 *)

Formula

a(n) = Sum_{i=n(n-1)/2+1..n(n-1)/2+n} i^10.
a(n) = (33n^21 + 825n^19 + 6336n^17 + 18546n^15 + 14289n^13 - 14187n^11 - 418n^9 + 20592n^7 - 10560n^5 - 4224n^3 + 2560n)/33792. - Charles R Greathouse IV, Sep 17 2009
G.f.: (x^20 +60051*x^19 +69959002*x^18 +13288708503*x^17 +781445555829*x^16 +19040717780376*x^15 +225625446425352*x^14 +1431958892640624*x^13 +5170348336132746*x^12 +11021721646301518*x^11 +14154518527431996*x^10 +11021721646301518*x^9 +5170348336132746*x^8 +1431958892640624*x^7 +225625446425352*x^6 +19040717780376*x^5 +781445555829*x^4 +13288708503*x^3 +69959002*x^2 +60051*x +1) / (x -1)^22. - Colin Barker, Dec 19 2012

Extensions

More terms from Colin Barker, Dec 19 2012

A072475 Sum of next n composite numbers.

Original entry on oeis.org

4, 14, 31, 63, 112, 176, 264, 385, 529, 712, 932, 1184, 1503, 1833, 2234, 2689, 3207, 3779, 4408, 5117, 5913, 6747, 7657, 8667, 9766, 10938, 12240, 13612, 15071, 16578, 18266, 20081, 22007, 23989, 26100, 28334, 30695, 33221, 35811, 38569, 41474
Offset: 1

Views

Author

Amarnath Murthy, Jun 20 2002

Keywords

Crossrefs

Programs

  • Mathematica
    Composite[n_Integer] := FixedPoint[n + PrimePi[ # ] + 1 &, n + PrimePi[n] + 1]; Table[ Sum[ Composite[i], {i, n(n - 1)/2 + 1, n(n + 1)/2}], {n, 1, 42}]
    With[{terms=50},cnos=With[{c=(terms(terms+1)(terms+2))/6}, Complement[ Range[5,c], Prime[Range[PrimePi[c]]]]];Join[{4}, Total/@Table[Take[ cnos,{n (n+1)/2,(n+1) (n+2)/2-1}],{n,terms-1}]]] (* Harvey P. Dale, Oct 10 2011 *)

Extensions

More terms from Jim Nastos and Robert G. Wilson v, Jun 21 2002

A372583 a(n) = (3*n^5 + 5*n^3)/8.

Original entry on oeis.org

1, 17, 108, 424, 1250, 3051, 6517, 12608, 22599, 38125, 61226, 94392, 140608, 203399, 286875, 395776, 535517, 712233, 932824, 1205000, 1537326, 1939267, 2421233, 2994624, 3671875, 4466501, 5393142, 6467608, 7706924, 9129375, 10754551, 12603392, 14698233
Offset: 1

Views

Author

Kelvin Voskuijl, May 05 2024

Keywords

Comments

Sum of pentagonal numbers in increasing groups 1, 5+12, 22+35+51, 70+92+117+145 etc.

Examples

			The first ten pentagonal numbers are 1, 5, 12, 22, 35, 51, 70, 92, 117, and 145.  Taking them in groups, respectively, of 1, 2, 3, and 4, i.e., (1), (5, 12), (22, 35, 51), and (70, 92, 117, 145), and summing each group separately gives 1, 17, 108, 424.
		

Crossrefs

Cf. A260513 (for triangular numbers), A072474 (for squares).
Cf. A000326 (pentagonal numbers), A002411 (their partial sums).

Programs

Formula

From Stefano Spezia, May 06 2024: (Start)
G.f.: x*(1 + 11*x + 21*x^2 + 11*x^3 + x^4)/(1 - x)^6.
E.g.f.: exp(x)*x*(8 + 60*x + 80*x^2 + 30*x^3 + 3*x^4)/8. (End)

A075665 Sum of next n 4th powers.

Original entry on oeis.org

1, 97, 2177, 23058, 152979, 738835, 2839571, 9191876, 26037717, 66301333, 154762069, 336050870, 686502375, 1331121351, 2467171687, 4396168328, 7566347369, 12628007049, 20504452585, 32481640666, 50320004987, 76392352443, 113852150523, 166836980044, 240712403645
Offset: 1

Views

Author

Zak Seidov, Sep 24 2002

Keywords

Examples

			a(1) = 1^4 = 1; a(2) = 2^4 + 3^4 = 97; a(3) = 4^4 + 5^4 + 6^4 = 2177; a(4) = 7^4 + 8^4 + 9^4 + 10^4 = 23058.
		

Crossrefs

Cf. A000583 (4th powers).
Cf. A006003 (for natural numbers), A072474 (for squares), A075664 - A075671 (3rd to 10th powers), A069876 (n-th powers).

Programs

  • Mathematica
    i1 := n(n-1)/2+1; i2 := n(n-1)/2+n; s=4; Table[Sum[i^s, {i, i1, i2}], {n, 20}]
    Table[Total[Range[(n(n+1))/2+1,((n+1)(n+2))/2]^4],{n,0,20}] (* or *) LinearRecurrence[{10,-45,120,-210,252,-210,120,-45,10,-1},{1,97,2177,23058,152979,738835,2839571,9191876,26037717,66301333},30] (* Harvey P. Dale, Dec 18 2015 *)

Formula

a(n) = Sum_{i=n*(n-1)/2+1..n*(n-1)/2+n} i^4.
a(n) = (15*n^9 + 90*n^7 + 123*n^5 + 20*n^3 - 8*n)/240. - Charles R Greathouse IV, Sep 17 2009
G.f.: x*(1+87*x+1252*x^2+5533*x^3+8934*x^4+5533*x^5+1252*x^6+87*x^7+x^8)/ (1-x)^10. - Colin Barker, May 25 2012

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

A372751 a(n) = (3*n^5 + 4*n^3 - n)/6.

Original entry on oeis.org

1, 21, 139, 554, 1645, 4031, 8631, 16724, 30009, 50665, 81411, 125566, 187109, 270739, 381935, 527016, 713201, 948669, 1242619, 1605330, 2048221, 2583911, 3226279, 3990524, 4893225, 5952401, 7187571, 8619814, 10271829, 12167995, 14334431, 16799056, 19591649
Offset: 1

Views

Author

Kelvin Voskuijl, May 12 2024

Keywords

Comments

Sums of hexagonal numbers (A000384) in successive groups of length 1,2,3,etc, so 1, 6+15, 28+45+66, 91+120+153+190, etc.

Examples

			The hexagonal numbers and their groups summed begin
  1, 6, 15, 28, 45, 66, 91, 120, 153, 190
  \/ \---/  \--------/  \---------------/
  1,   21,     139,            554
		

Crossrefs

Cf. A000384 (hexagonal numbers), A002412 (their partial sums).
Cf. A260513 (for triangular numbers), A072474 (for squares), A372583 (for pentagonal numbers), A075664 (cubes).

Programs

Formula

From Stefano Spezia, May 12 2024: (Start)
G.f.: x*(1 + 15*x + 28*x^2 + 15*x^3 + x^4)/(1 - x)^6.
E.g.f.: exp(x)*x*(6 + 57*x + 79*x^2 + 30*x^3 + 3*x^4)/6. (End)

A380353 a(n) = (n^2 - n + 2) * (5*n^2 - 5*n + 2) / 4.

Original entry on oeis.org

1, 12, 64, 217, 561, 1216, 2332, 4089, 6697, 10396, 15456, 22177, 30889, 41952, 55756, 72721, 93297, 117964, 147232, 181641, 221761, 268192, 321564, 382537, 451801, 530076, 618112, 716689, 826617, 948736, 1083916, 1233057, 1397089, 1576972, 1773696, 1988281, 2221777
Offset: 1

Views

Author

Kelvin Voskuijl, Jan 22 2025

Keywords

Comments

First differences of A072474 (sum of next n squares).

Crossrefs

Cf. A072474 (partial sums), A051624, A000124.
Cf. A005448 (first difference of sum of next n natural numbers).

Programs

  • Mathematica
    Table[((n^2 - n + 2)*(5*n^2 - 5*n + 2))/4, {n, 1, 40}]
  • PARI
    a(n) = (n^2 - n + 2) * (5*n^2 - 5*n + 2) / 4

Formula

a(n) = A051624(A000124(n-1)).
G.f.: x*(1+3*x+x^2)*(1+4*x+x^2)/(1-x)^5. - Jinyuan Wang, Jan 23 2025
E.g.f.: exp(x)*(4 + 22*x^2 + 20*x^3 + 5*x^4)/4 - 1. - Stefano Spezia, Jan 28 2025
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