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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A007587 12-gonal (or dodecagonal) pyramidal numbers: a(n) = n*(n+1)*(10*n-7)/6.

Original entry on oeis.org

0, 1, 13, 46, 110, 215, 371, 588, 876, 1245, 1705, 2266, 2938, 3731, 4655, 5720, 6936, 8313, 9861, 11590, 13510, 15631, 17963, 20516, 23300, 26325, 29601, 33138, 36946, 41035, 45415, 50096, 55088, 60401, 66045, 72030, 78366, 85063, 92131, 99580, 107420, 115661
Offset: 0

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Author

Keywords

Comments

Binomial transform of [1, 12, 21, 10, 0, 0, 0, ...] = (1, 13, 46, 110, ...). - Gary W. Adamson, Nov 28 2007
This sequence is related to A000566 by a(n) = n*A000566(n) - Sum_{i=0..n-1} A000566(i) and this is the case d=5 in the identity n*(n*(d*n-d+2)/2) - Sum_{k=0..n-1} k*(d*k-d+2)/2 = n*(n+1)*(2*d*n - 2*d + 3)/6. - Bruno Berselli, Oct 18 2010

References

  • A. H. Beiler, Recreations in the Theory of Numbers, Dover, NY, 1964, p. 194.
  • E. Deza and M. M. Deza, Figurate numbers, World Scientific Publishing (2012), page 93.
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Cf. A093645 ((10, 1) Pascal, column m=3). Partial sums of A051624.
Cf. A000566.
See similar sequences listed in A237616.

Programs

  • GAP
    List([0..45], n-> n*(n+1)*(10*n-7)/6); # G. C. Greubel, Aug 30 2019
  • Magma
    [ n eq 1 select 0 else Self(n-1)+(n-1)*(5*n-9): n in [1..45] ]; // Klaus Brockhaus, Nov 20 2008
    
  • Maple
    A007587:=n->n*(n+1)*(10*n-7)/6: seq(A007587(n), n=0..50); # Wesley Ivan Hurt, Oct 23 2014
  • Mathematica
    CoefficientList[Series[x(1+9x)/(1-x)^4, {x,0,45}], x] (* Vincenzo Librandi, Jun 20 2013 *)
    Table[n(n+1)(10n-7)/6,{n,0,50}] (* Harvey P. Dale, Nov 13 2013 *)
  • PARI
    a(n)=if(n,([0,1,0,0; 0,0,1,0; 0,0,0,1; -1,4,-6,4]^n*[0;1;13;46])[1,1],0) \\ Charles R Greathouse IV, Oct 07 2015
    
  • PARI
    vector(45, n, n*(n-1)*(10*n-17)/6) \\ G. C. Greubel, Aug 30 2019
    
  • Sage
    [n*(n+1)*(10*n-7)/6 for n in (0..45)] # G. C. Greubel, Aug 30 2019
    

Formula

a(n) = (10*n-7)*binomial(n+1, 2)/3.
G.f.: x*(1+9*x)/(1-x)^4.
a(n) = Sum_{k=0..n} k*(5*k-4). - Klaus Brockhaus, Nov 20 2008
a(n) = Sum_{i=0..n-1} (n-i)*(10*i+1), with a(0)=0. - Bruno Berselli, Feb 10 2014
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4). - Wesley Ivan Hurt, Oct 23 2014
E.g.f.: exp(x)*x*(6 + 33*x + 10*x^2)/6. - Elmo R. Oliveira, Aug 04 2025

A172073 a(n) = (4*n^3 + n^2 - 3*n)/2.

Original entry on oeis.org

0, 1, 15, 54, 130, 255, 441, 700, 1044, 1485, 2035, 2706, 3510, 4459, 5565, 6840, 8296, 9945, 11799, 13870, 16170, 18711, 21505, 24564, 27900, 31525, 35451, 39690, 44254, 49155, 54405, 60016, 66000, 72369, 79135, 86310, 93906, 101935, 110409, 119340, 128740
Offset: 0

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Author

Vincenzo Librandi, Jan 25 2010

Keywords

Comments

14-gonal (or tetradecagonal) pyramidal numbers generated by the formula n*(n+1)*(2*d*n-(2*d-3))/6 for d=6.
In fact, the sequence is related to A000567 by a(n) = n*A000567(n) - Sum_{i=0..n-1} A000567(i) and this is the case d=6 in the identity n*(n*(d*n-d+2)/2) - Sum_{k=0..n-1} k*(d*k-d+2)/2 = n*(n+1)*(2*d*n-2*d+3)/6. - Bruno Berselli, Nov 29 2010
Except for the initial 0, this is the principal diagonal of the convolution array A213761. - Clark Kimberling, Jul 04 2012
Starting (1, 15, 54, ...), this is the binomial transform of (1, 14, 25, 12, 0, 0, 0, ...). - Gary W. Adamson, Jul 29 2015

References

  • E. Deza and M. M. Deza, Figurate numbers, World Scientific Publishing (2012), page 93. - Bruno Berselli, Feb 13 2014

Crossrefs

Cf. similar sequences listed in A237616.

Programs

  • GAP
    List([0..40], n-> n*(n+1)*(4*n-3)/2); # G. C. Greubel, Aug 30 2019
  • Magma
    [(4*n^3+n^2-3*n)/2: n in [0..50]]; // Vincenzo Librandi, Jan 01 2014
    
  • Maple
    seq(n*(n+1)*(4*n-3)/2, n=0..40); # G. C. Greubel, Aug 30 2019
  • Mathematica
    f[n_]:= n(n+1)(4n-3)/2; Array[f, 40, 0]
    LinearRecurrence[{4,-6,4,-1},{0,1,15,54},40] (* Harvey P. Dale, Jan 29 2013 *)
    CoefficientList[Series[x (1+11x)/(1-x)^4, {x, 0, 40}], x] (* Vincenzo Librandi, Jan 01 2014 *)
  • PARI
    a(n)=(4*n^3+n^2-3*n)/2 \\ Charles R Greathouse IV, Oct 07 2015
    
  • Sage
    [n*(n+1)*(4*n-3)/2 for n in (0..40)] # G. C. Greubel, Aug 30 2019
    

Formula

a(n) = n*(n+1)*(4*n-3)/2.
From Bruno Berselli, Dec 15 2010: (Start)
G.f.: x*(1+11*x)/(1-x)^4.
a(n) = Sum_{i=0..n} A051866(i). (End)
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4) for n > 3, a(0)=0, a(1)=1, a(2)=15, a(3)=54. - Harvey P. Dale, Jan 29 2013
a(n) = Sum_{i=0..n-1} (n-i)*(12*i+1), with a(0)=0. - Bruno Berselli, Feb 10 2014
From Amiram Eldar, Jan 10 2022: (Start)
Sum_{n>=1} 1/a(n) = 4*Pi/21 + 8*log(2)/7 - 2/7.
Sum_{n>=1} (-1)^(n+1)/a(n) = 4*sqrt(2)*Pi/21 + 8*sqrt(2)*log(sqrt(2)+2)/21 - (20 + 4*sqrt(2))*log(2)/21 + 2/7. (End)
E.g.f.: exp(x)*x*(2 + 13*x + 4*x^2)/2. - Elmo R. Oliveira, Aug 04 2025

Extensions

Edited by Bruno Berselli, Dec 14 2010

A172078 a(n) = n*(16*n^2 + 3*n - 13)/6.

Original entry on oeis.org

0, 1, 19, 70, 170, 335, 581, 924, 1380, 1965, 2695, 3586, 4654, 5915, 7385, 9080, 11016, 13209, 15675, 18430, 21490, 24871, 28589, 32660, 37100, 41925, 47151, 52794, 58870, 65395, 72385, 79856, 87824, 96305, 105315, 114870, 124986, 135679
Offset: 0

Views

Author

Vincenzo Librandi, Jan 25 2010

Keywords

Comments

Generated by the formula n*(n+1)*(2*d*n-(2*d-3))/6 for d=8.
In fact, the sequence is related to A001107 by a(n) = n*A001107(n) - Sum_{k=0..n-1} A001107(k), and this is the case d=8 in the identity n*(n*(d*n-d+2)/2) - Sum_{k=0..n-1} k*(d*k-d+2)/2 = n*(n+1)*(2*d*n-2*d+3)/6. - Bruno Berselli, Dec 14 2010
Inverse binomial transform of this sequence: 0, 1, 17, 16, 0, 0 (0 continued). - Bruno Berselli, Dec 14 2010
Principal diagonal of the convolution array A213835. - Clark Kimberling, Jul 04 2012

References

  • E. Deza and M. M. Deza, Figurate numbers, World Scientific Publishing (2012), page 93. - Bruno Berselli, Feb 13 2014

Crossrefs

Cf. A001107.
Cf. similar sequences listed in A237616.

Programs

Formula

a(n) = n*(n+1)*(16*n-13)/6.
G.f.: x*(1+15*x)/(1-x)^4. - Bruno Berselli, Dec 14 2010
a(n) = Sum_{i=0..n-1} (n-i)*(16*i+1), with a(0)=0. - Bruno Berselli, Feb 10 2014
E.g.f.: x*(6 +51*x +16*x^2)*exp(x)/6. - G. C. Greubel, Aug 30 2019

A050441 Partial sums of A051865.

Original entry on oeis.org

0, 1, 14, 50, 120, 235, 406, 644, 960, 1365, 1870, 2486, 3224, 4095, 5110, 6280, 7616, 9129, 10830, 12730, 14840, 17171, 19734, 22540, 25600, 28925, 32526, 36414, 40600, 45095, 49910, 55056, 60544, 66385, 72590, 79170, 86136, 93499, 101270
Offset: 0

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Author

Barry E. Williams, Dec 23 1999

Keywords

Comments

This sequence is related to A180223 by 2*a(n) = n*A180223(n) - Sum_{i=0..n-1} A180223(i). Also, 13-gonal (or tridecagonal) pyramidal numbers. - Bruno Berselli, Dec 14 2010

Examples

			After 0, the sequence is provided by the row sums of the triangle (see above, fourth formula):
  1;
  2, 12;
  3, 24, 23;
  4, 36, 46, 34;
  5, 48, 69, 68, 45; ... - _Vincenzo Librandi_, Feb 12 2014
		

References

  • A. H. Beiler, Recreations in the Theory of Numbers, Dover, N.Y., 1964, pp. 189-196.
  • E. Deza and M. M. Deza, Figurate numbers, World Scientific Publishing (2012), page 93.

Crossrefs

Similar sequences are listed in A237616.

Programs

  • GAP
    List([0..40], n-> n*(n+1)*(11*n-8)/6); # G. C. Greubel, Aug 30 2019
  • Magma
    I:=[0,1,14,50]; [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, Feb 12 2014
    
  • Maple
    seq(n*(n+1)*(11*n-8)/6, n=0..40); # G. C. Greubel, Aug 30 2019
  • Mathematica
    Accumulate[Table[n (11n-9)/2,{n,0,40}]] (* or *) LinearRecurrence[ {4,-6,4,-1},{0,1,14,50},40] (* Harvey P. Dale, Nov 14 2011 *)
    CoefficientList[Series[x (1 + 10 x)/(1 - x)^4, {x, 0, 40}], x] (* Vincenzo Librandi, Feb 12 2014 *)
  • PARI
    a(n)=n*(n+1)*(11*n-8)/6 \\ Charles R Greathouse IV, Oct 07 2015
    
  • Sage
    [n*(n+1)*(11*n-8)/6 for n in (0..40)] # G. C. Greubel, Aug 30 2019
    

Formula

a(n) = n*(n+1)*(11*n-8)/6.
G.f.: x*(1+10*x)/(1-x)^4. - Bruno Berselli, Aug 19 2010
a(n) = 4*a(n-1)-6*a(n-2)+4*a(n-3)-a(n-4). - Bruno Berselli, Aug 19 2010
a(n) = Sum_{i=0..n-1} (n-i)*(11*i+1), with a(0)=0. - Bruno Berselli, Feb 10 2014
E.g.f.: exp(x)*x*(6 + 36*x + 11*x^2)/6. - Stefano Spezia, May 04 2022

A172076 a(n) = n*(n+1)*(14*n-11)/6.

Original entry on oeis.org

0, 1, 17, 62, 150, 295, 511, 812, 1212, 1725, 2365, 3146, 4082, 5187, 6475, 7960, 9656, 11577, 13737, 16150, 18830, 21791, 25047, 28612, 32500, 36725, 41301, 46242, 51562, 57275, 63395, 69936, 76912, 84337, 92225, 100590, 109446, 118807, 128687
Offset: 0

Views

Author

Vincenzo Librandi, Jan 25 2010

Keywords

Comments

Generated by the formula n*(n+1)*(2*d*n-(2*d-3))/6 for d=7.
From Bruno Berselli, Dec 14 2010: (Start)
In fact, the sequence is related to A001106 by a(n) = n*A001106(n) - Sum_{k=0..n-1} A001106(k) and this is the case d=7 in the identity n*(n*(d*n-d+2)/2) - Sum_{k=0..n-1} k*(d*k-d+2)/2 = n*(n+1)*(2*d*n-2*d+3)/6.
Also 16-gonal (or hexadecagonal) pyramidal numbers.
Inverse binomial transform of this sequence: 0, 1, 15, 14, 0, 0 (0 continued). (End)

References

  • E. Deza and M. M. Deza, Figurate numbers, World Scientific Publishing (2012), page 93. [From Bruno Berselli, Feb 13 2014]

Crossrefs

Cf. similar sequences listed in A237616.

Programs

Formula

G.f.: x*(1+13*x)/(1-x)^4. - Bruno Berselli, Dec 15 2010
a(n) = Sum_{i=0..n} A051868(i). - Bruno Berselli, Dec 15 2010
a(n) = Sum_{i=0..n-1} (n-i)*(14*i+1), with a(0)=0. - Bruno Berselli, Feb 10 2014
E.g.f.: x*(6 + 45*x + 14*x^2)*exp(x)/6. - G. C. Greubel, Aug 30 2019

A172082 a(n) = n*(n+1)*(6*n-5)/2.

Original entry on oeis.org

0, 1, 21, 78, 190, 375, 651, 1036, 1548, 2205, 3025, 4026, 5226, 6643, 8295, 10200, 12376, 14841, 17613, 20710, 24150, 27951, 32131, 36708, 41700, 47125, 53001, 59346, 66178, 73515, 81375, 89776, 98736, 108273, 118405, 129150, 140526
Offset: 0

Views

Author

Vincenzo Librandi, Jan 25 2010

Keywords

Comments

Generated by formula: n*(n+1)*(2*d*n-2*d+3)/6 with d=9.
This sequence is related to A051682 by a(n) = n*A051682(n) - Sum_{i=0..n-1} A051682(i); in fact this is the case d=9 in the identity n*(n*(d*n-d+2)/2) - Sum_{i=0..n-1} i*(d*i-d+2)/2 = n*(n+1)*(2*d*n -2*d + 3)/6. - Bruno Berselli, Apr 16 2012

References

  • E. Deza and M. M. Deza, Figurate numbers, World Scientific Publishing (2012), page 93. - Bruno Berselli, Feb 13 2014

Crossrefs

Cf. A051682.
Cf. similar sequences listed in A237616.

Programs

  • GAP
    List([0..40], n-> n*(n+1)*(6*n-5)/2); # G. C. Greubel, Aug 30 2019
  • Magma
    [(18*n^3+3*n^2-15*n)/6: n in [0..40]]; // Vincenzo Librandi, Jan 02 2014
    
  • Maple
    seq(n*(n+1)*(6*n-5)/2, n=0..40); # G. C. Greubel, Aug 30 2019
  • Mathematica
    Table[(18n^3+3n^2-15n)/6,{n,0,40}] (* or *) LinearRecurrence[{4,-6,4,-1}, {0,1,21,78}, 40] (* Harvey P. Dale, Jun 29 2011 *)
    CoefficientList[Series[x*(1+17*x)/(1-x)^4, {x,0,40}], x] (* Vincenzo Librandi, Jan 02 2014 *)
  • PARI
    vector(40, n, n*(n-1)*(6*n-11)/2) \\ G. C. Greubel, Aug 30 2019
    
  • Sage
    [n*(n+1)*(6*n-5)/2 for n in (0..40)] # G. C. Greubel, Aug 30 2019
    

Formula

a(0)=0, a(1)=1, a(2)=21, a(3)=78; for n>3, a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4). - Harvey P. Dale, Jun 29 2011
G.f.: x*(1+17*x)/(1-x)^4. - Harvey P. Dale, Jun 29 2011
a(n) = Sum_{i=0..n-1} (n-i)*(18*i+1), with a(0)=0. - Bruno Berselli, Feb 10 2014
E.g.f.: x*(2 + 19*x + 6*x^2)*exp(x)/2. - G. C. Greubel, Aug 30 2019
From Amiram Eldar, Jan 10 2022: (Start)
Sum_{n>=1} 1/a(n) = 2*(3*sqrt(3)*Pi + 9*log(3) + 12*log(2) - 5)/55.
Sum_{n>=1} (-1)^(n+1)/a(n) = 2*(6*Pi + 6*sqrt(3)*log(sqrt(3)+2) - 16*log(2) + 5)/55. (End)

A172117 a(n) = n*(n+1)*(20*n-17)/6.

Original entry on oeis.org

0, 1, 23, 86, 210, 415, 721, 1148, 1716, 2445, 3355, 4466, 5798, 7371, 9205, 11320, 13736, 16473, 19551, 22990, 26810, 31031, 35673, 40756, 46300, 52325, 58851, 65898, 73486, 81635, 90365, 99696, 109648, 120241, 131495, 143430, 156066
Offset: 0

Views

Author

Vincenzo Librandi, Jan 26 2010

Keywords

Comments

Generated by the formula n*(n+1)*(2*d*n-2*d+3)/6 for d=10.
This sequence is related to A051624 by a(n) = n*A051624(n) - Sum_{i=0..n-1} A051624(i) = n*(n+1)*(20*n-17)/2; in fact, this is the case d=10 in the identity n*(n*(d*n-d+2)/2) - Sum_{i=0..n-1} i*(d*i-d+2)/2 = n*(n+1)*(2*d*n-2*d+3)/6. - Bruno Berselli, Aug 26 2010
Also, a(n) = n*A190816(n) - Sum_{i=0..n-1} A190816(i) for n>0. - Bruno Berselli, Dec 18 2013
Starting with offset 1, the sequence is the binomial transform of (1, 22, 41, 20, 0, 0, 0, ...). - Gary W. Adamson, Jul 31 2015

References

  • E. Deza and M. M. Deza, Figurate numbers, World Scientific Publishing (2012), page 93. [Bruno Berselli, Feb 13 2014]

Crossrefs

Cf. A051624.
Cf. similar sequences listed in A237616.

Programs

  • Magma
    [n*(n+1)*(20*n-17)/6: n in [0..50]]; // Vincenzo Librandi, Aug 01 2015
    
  • Mathematica
    Table[(20n^3+3n^2-17n)/6,{n,0,50}] (* or *) LinearRecurrence[{4,-6,4,-1},{0,1,23,86},40] (* Harvey P. Dale, May 15 2011 *)
  • PARI
    a(n)=n*(20*n^2+3*n-17)/6 \\ Charles R Greathouse IV, Jan 11 2012
    
  • SageMath
    [sum( (-1)^j*(20-j)*binomial(n+2-j, 3-j) for j in (0..1)) for n in (0..50)] # G. C. Greubel, Apr 15 2022

Formula

G.f.: x*(1+19*x)/(1-x)^4. - Bruno Berselli, Aug 26 2010
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4) for n > 3. - Harvey P. Dale, May 15 2011
a(n) = Sum_{i=0..n-1} (n-i)*(20*i+1), with a(0)=0. - Bruno Berselli, Feb 11 2014
E.g.f.: (1/6)*x*(6 + 63*x + 20*x^2)*exp(x). - G. C. Greubel, Apr 15 2022

A256716 a(n) = n*(n+1)*(22*n-19)/6.

Original entry on oeis.org

0, 1, 25, 94, 230, 455, 791, 1260, 1884, 2685, 3685, 4906, 6370, 8099, 10115, 12440, 15096, 18105, 21489, 25270, 29470, 34111, 39215, 44804, 50900, 57525, 64701, 72450, 80794, 89755, 99355, 109616, 120560, 132209, 144585, 157710, 171606, 186295, 201799, 218140
Offset: 0

Views

Author

Bruno Berselli, Apr 09 2015

Keywords

Comments

This sequence is related to the tridecagonal numbers (A051865) by a(n) = n*A051865(n) - Sum_{i=0..n-1} A051865(i).

References

  • E. Deza and M. M. Deza, Figurate numbers, World Scientific Publishing (2012), page 93 (22nd row of the table).

Crossrefs

Partial sums of A051876.
Cf. similar sequences listed in A237616.
Cf. A051865.

Programs

  • Magma
    [n*(n+1)*(22*n-19)/6: n in [0..40]];
  • Mathematica
    Table[n (n + 1) (22 n - 19)/6, {n, 0, 40}]
  • PARI
    vector(40, n, n--; n*(n+1)*(22*n-19)/6)
    
  • Sage
    [n*(n+1)*(22*n-19)/6 for n in (0..40)]
    

Formula

G.f.: x*(1 + 21*x)/(1 - x)^4.
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4) with n>3, a(0)=0, a(1)=1, a(2)=25, a(3)=94.
a(n) = Sum_{i=0..n-1} (n-i)*(22*i+1) for n>0.
E.g.f.: exp(x)*x*(6 + 69*x + 22*x^2)/6. - Elmo R. Oliveira, Aug 04 2025

A177890 15-gonal (or pentadecagonal) pyramidal numbers: a(n) = n*(n+1)*(13*n-10)/6.

Original entry on oeis.org

0, 1, 16, 58, 140, 275, 476, 756, 1128, 1605, 2200, 2926, 3796, 4823, 6020, 7400, 8976, 10761, 12768, 15010, 17500, 20251, 23276, 26588, 30200, 34125, 38376, 42966, 47908, 53215, 58900, 64976, 71456, 78353, 85680, 93450, 101676, 110371, 119548, 129220
Offset: 0

Views

Author

Bruno Berselli, Dec 14 2010

Keywords

Comments

Also a(n) = (15-m)*A000292(n-1) + n*(n+1)*((m-2)*n - (m-5))/6 being n*(n+1)*((m-2)*n - (m-5))/6 a m-gonal pyramidal number (1 < m < 15). For m=6, a(n) = 9*A000292(n-1) + A002412(n).
Inverse binomial transform of this sequence: 0, 1, 14, 13, 0, 0 (0 continued).

References

  • E. Deza and M. M. Deza, Figurate numbers, World Scientific Publishing (2012), page 93 (thirteenth row of the table).

Crossrefs

Cf. similar sequences listed in A237616.

Programs

  • GAP
    List([0..40], n-> n*(n+1)*(13*n-10)/6); # G. C. Greubel, Aug 30 2019
  • Magma
    I:=[0,1,16,58]; [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..40]]; // Vincenzo Librandi, Jul 04 2012
    
  • Magma
    [n*(n+1)*(13*n-10)/6: n in [0..40]]; // G. C. Greubel, Aug 30 2019
    
  • Maple
    seq(n*(n+1)*(13*n-10)/6, n=0..40); # G. C. Greubel, Aug 30 2019
  • Mathematica
    CoefficientList[Series[x*(1+12*x)/(1-x)^4,{x,0,40}],x] (* Vincenzo Librandi, Jul 04 2012 *)
    Table[n*(n-1)*(13*n-23)/6, {n,40}] (* G. C. Greubel, Aug 30 2019 *)
    LinearRecurrence[{4,-6,4,-1},{0,1,16,58},40] (* Harvey P. Dale, Dec 21 2022 *)
  • PARI
    vector(40, n, n*(n-1)*(13*n-23)/6) \\ G. C. Greubel, Aug 30 2019
    
  • Sage
    [n*(n+1)*(13*n-10)/6 for n in (0..40)] # G. C. Greubel, Aug 30 2019
    

Formula

G.f.: x*(1+12*x)/(1-x)^4.
a(n) = Sum_{i=0..n} A051867(i).
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4). - Vincenzo Librandi, Jul 04 2012
a(n) = Sum_{i=0..n-1} (n-i)*(13*i+1), with a(0)=0. - Bruno Berselli, Feb 10 2014
E.g.f.: x*(6 + 42*x + 13*x^2)*exp(x)/6. - G. C. Greubel, Aug 30 2019

A237617 a(n) = n*(n + 1)*(17*n - 14)/6.

Original entry on oeis.org

0, 1, 20, 74, 180, 355, 616, 980, 1464, 2085, 2860, 3806, 4940, 6279, 7840, 9640, 11696, 14025, 16644, 19570, 22820, 26411, 30360, 34684, 39400, 44525, 50076, 56070, 62524, 69455, 76880, 84816, 93280, 102289, 111860, 122010, 132756, 144115, 156104, 168740
Offset: 0

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Author

Bruno Berselli, Feb 11 2014

Keywords

Comments

Also 19-gonal (or nonadecagonal) pyramidal numbers.
This sequence is related to A180232 by 2*a(n) = n*A180232(n) - Sum_{i=0..n-1} A180232(i).

Examples

			After 0, the sequence is provided by the row sums of the triangle:
   1;
   2,  18;
   3,  36,  35;
   4,  54,  70,  52;
   5,  72, 105, 104,  69;
   6,  90, 140, 156, 138,  86;
   7, 108, 175, 208, 207, 172, 103;
   8, 126, 210, 260, 276, 258, 206, 120;
   9, 144, 245, 312, 345, 344, 309, 240, 137;
  10, 162, 280, 364, 414, 430, 412, 360, 274, 154; etc.,
where (r = row index, c = column index):
T(r,r) = T(c,c) = 17*r - 16 and T(r,c) = T(r-1,c) + T(r,r) = (r-c+1) * T(r,r), with r>=c>0.
		

References

  • E. Deza and M. M. Deza, Figurate numbers, World Scientific Publishing (2012), page 93 (seventeenth row of the table).

Crossrefs

Cf. similar sequences listed in A237616.

Programs

  • GAP
    List([0..40], n-> n*(n+1)*(17*n-14)/6); # G. C. Greubel, Aug 30 2019
  • Magma
    [n*(n+1)*(17*n-14)/6: n in [0..40]];
    
  • Magma
    I:=[0,1,20,74]; [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..40]]; // Vincenzo Librandi, Feb 12 2014
    
  • Maple
    seq(n*(n+1)*(17*n-14)/6, n=0..40); # G. C. Greubel, Aug 30 2019
  • Mathematica
    Table[n(n+1)(17*n-14)/6, {n, 0, 40}]
    CoefficientList[Series[x(1+16x)/(1-x)^4, {x,0,40}], x] (* Vincenzo Librandi, Feb 12 2014 *)
    LinearRecurrence[{4,-6,4,-1},{0,1,20,74},40] (* Harvey P. Dale, Aug 04 2021 *)
  • PARI
    vector(40, n, n*(n-1)*(17*n-31)/6) \\ G. C. Greubel, Aug 30 2019
    
  • Sage
    [n*(n+1)*(17*n-14)/6 for n in (0..40)] # G. C. Greubel, Aug 30 2019
    

Formula

G.f.: x*(1 + 16*x)/(1 - x)^4.
For n>0, a(n) = Sum_{i=0..n-1} (n-i)*(17*i+1); see the generalization in A237616 (Formula field).
E.g.f.: x*(6 + 54*x + 17*x^2)*exp(x)/6. - G. C. Greubel, Aug 30 2019
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