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 396 results. Next

A000391 Euler transform of A000332.

Original entry on oeis.org

1, 6, 21, 71, 216, 672, 1982, 5817, 16582, 46633, 128704, 350665, 941715, 2499640, 6557378, 17024095, 43756166, 111433472, 281303882, 704320180, 1749727370, 4314842893, 10565857064, 25700414815, 62115621317, 149214574760, 356354881511, 846292135184
Offset: 1

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Author

Keywords

References

  • 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

Programs

  • Maple
    with(numtheory): etr:= proc(p) local b; b:=proc(n) option remember; local d,j; if n=0 then 1 else add(add(d*p(d), d=divisors(j)) *b(n-j), j=1..n)/n fi end end: a:= etr(n-> binomial(n+3,4)): seq(a(n), n=1..30); # Alois P. Heinz, Sep 08 2008
  • Mathematica
    nn = 50; b = Table[Binomial[n, 4], {n, 4, nn + 4}]; Rest[CoefficientList[Series[Product[1/(1 - x^m)^b[[m]], {m, nn}], {x, 0, nn}], x]] (* T. D. Noe, Jun 21 2012 *)
    nmax=50; Rest[CoefficientList[Series[Product[1/(1-x^k)^(k*(k+1)*(k+2)*(k+3)/24),{k,1,nmax}],{x,0,nmax}],x]] (* Vaclav Kotesovec, Mar 11 2015 *)
  • PARI
    a(n)=if(n<0, 0, polcoeff(exp(sum(k=1, n, x^k/(1-x^k)^5/k, x*O(x^n))), n)) /* Joerg Arndt, Apr 16 2010 */

Formula

a(n) ~ Pi^(3/160) / (2 * 3^(243/320) * 7^(83/960) * n^(563/960)) * exp(Zeta'(-1)/4 - 143 * Zeta(3) / (240 * Pi^2) + 53461 * Zeta(5) / (3200 * Pi^4) + 107163 * Zeta(3) * Zeta(5)^2 / (2*Pi^12) - 24754653 * Zeta(5)^3 / (10*Pi^14) + 413420708484 * Zeta(5)^5 / (5*Pi^24) + Zeta'(-3)/4 + (-847 * 7^(1/6) * Pi / (19200 * sqrt(3)) - 189 * sqrt(3) * 7^(1/6) * Zeta(3) * Zeta(5) / (2*Pi^7) + 305613 * sqrt(3) * 7^(1/6) * Zeta(5)^2 / (80*Pi^9) - 614365479 * sqrt(3) * 7^(1/6) * Zeta(5)^4 / (4*Pi^19)) * n^(1/6) + (3 * 7^(1/3) * Zeta(3) / (4*Pi^2) - 693 * 7^(1/3) * Zeta(5) / (40*Pi^4) + 857304 * 7^(1/3) * Zeta(5)^3 / Pi^14) * n^(1/3) + (11 * sqrt(7/3) * Pi / 120 - 1701 * sqrt(21) * Zeta(5)^2 / Pi^9) * sqrt(n) + 27 * 7^(2/3) * Zeta(5) / (2*Pi^4) * n^(2/3) + 2*sqrt(3)*Pi / (5*7^(1/6)) * n^(5/6)). - Vaclav Kotesovec, Mar 12 2015

A104392 Sums of 2 distinct positive pentatope numbers (A000332).

Original entry on oeis.org

6, 16, 20, 36, 40, 50, 71, 75, 85, 105, 127, 131, 141, 161, 196, 211, 215, 225, 245, 280, 331, 335, 336, 345, 365, 400, 456, 496, 500, 510, 530, 540, 565, 621, 705, 716, 720, 730, 750, 785, 825, 841, 925, 1002, 1006, 1016, 1036, 1045, 1071, 1127
Offset: 0

Views

Author

Jonathan Vos Post, Mar 05 2005

Keywords

Comments

Pentatope number Ptop(n) = binomial(n+3,4) = n*(n+1)*(n+2)*(n+3)/24. Hyun Kwang Kim asserts that every positive integer can be represented as the sum of no more than 8 pentatope numbers; but in this sequence we are only concerned with sums of nonzero distinct pentatope numbers.

References

  • Conway, J. H. and Guy, R. K. The Book of Numbers. New York: Springer-Verlag, pp. 55-57, 1996.

Crossrefs

Programs

  • Mathematica
    nn=15; Select[Union[Total/@Subsets[Binomial[Range[4,nn],4],{2}]], #Harvey P. Dale, Mar 13 2011 *)

Formula

a(n) = Ptop(i) + Ptop(j) for some positive i=/=j and Ptop(n) = binomial(n+3,4).

Extensions

Extended by Ray Chandler, Mar 05 2005

A104393 Sums of 3 distinct positive pentatope numbers (A000332).

Original entry on oeis.org

21, 41, 51, 55, 76, 86, 90, 106, 110, 120, 132, 142, 146, 162, 166, 176, 197, 201, 211, 216, 226, 230, 231, 246, 250, 260, 281, 285, 295, 315, 336, 337, 341, 346, 350, 351, 366, 370, 371, 380, 401, 405, 406, 415, 435, 457, 461, 471, 491, 501
Offset: 0

Views

Author

Jonathan Vos Post, Mar 05 2005

Keywords

Comments

Pentatope number Ptop(n) = binomial(n+3,4) = n*(n+1)*(n+2)*(n+3)/24. Hyun Kwang Kim asserts that every positive integer can be represented as the sum of no more than 8 pentatope numbers; but in this sequence we are only concerned with sums of nonzero distinct pentatope numbers.

References

  • Conway, J. H. and Guy, R. K. The Book of Numbers. New York: Springer-Verlag, pp. 55-57, 1996.

Crossrefs

Programs

  • Mathematica
    Total/@Subsets[Table[Binomial[n+3,4],{n,10}],{3}]//Sort (* Harvey P. Dale, Feb 14 2018 *)

Formula

a(n) = Ptop(i) + Ptop(j) + Ptop(k) for some positive i=/=j=/=k and Ptop(n) = binomial(n+3,4).

Extensions

Extended by Ray Chandler, Mar 05 2005

A145454 Exponential transform of binomial(n,4) = A000332.

Original entry on oeis.org

1, 0, 0, 0, 1, 5, 15, 35, 105, 756, 6510, 46530, 283470, 1667380, 11457446, 99776040, 969295145, 9298091180, 86154691680, 804769174536, 8052676029420, 88489327173660, 1038440150703340, 12501684521410700, 151866259113256611
Offset: 0

Views

Author

Alois P. Heinz, Oct 10 2008

Keywords

Comments

a(n) is the number of ways of placing n labeled balls into indistinguishable boxes, where in each filled box 4 balls are seen at the top.
a(n) is also the number of forests of labeled rooted trees of height at most 1, with n labels, where each root contains 4 labels.

Crossrefs

4th column of A145460, A143398.

Programs

  • Maple
    a:= proc(n) option remember; `if`(n=0, 1, add(
          binomial(n-1, j-1) *binomial(j,4) *a(n-j), j=1..n))
        end:
    seq(a(n), n=0..30);
  • Mathematica
    Table[Sum[BellY[n, k, Binomial[Range[n], 4]], {k, 0, n}], {n, 0, 25}] (* Vladimir Reshetnikov, Nov 09 2016 *)

Formula

E.g.f.: exp(exp(x)*x^4/4!).

A104394 Sums of 4 distinct positive pentatope numbers (A000332).

Original entry on oeis.org

56, 91, 111, 121, 125, 147, 167, 177, 181, 202, 212, 216, 231, 232, 236, 246, 251, 261, 265, 286, 296, 300, 316, 320, 330, 342, 351, 352, 356, 371, 372, 376, 381, 385, 386, 406, 407, 411, 416, 420, 421, 436, 440, 441, 450, 462, 472, 476, 492, 496
Offset: 1

Views

Author

Jonathan Vos Post, Mar 05 2005

Keywords

Comments

Pentatope number Ptop(n) = binomial(n+3,4) = n*(n+1)*(n+2)*(n+3)/24. Hyun Kwang Kim asserts that every positive integer can be represented as the sum of no more than 8 pentatope numbers; but in this sequence we are only concerned with sums of nonzero distinct pentatope numbers.

References

  • Conway, J. H. and Guy, R. K. The Book of Numbers. New York: Springer-Verlag, pp. 55-57, 1996.

Crossrefs

Formula

a(n) = Ptop(h) + Ptop(i) + Ptop(j) + Ptop(k) for some positive h=/=i=/=j=/=k and Ptop(n) = binomial(n+3,4).

Extensions

Extended by Ray Chandler, Mar 05 2005

A104395 Sums of 5 distinct positive pentatope numbers (A000332).

Original entry on oeis.org

126, 182, 217, 237, 247, 251, 266, 301, 321, 331, 335, 357, 377, 386, 387, 391, 412, 421, 422, 426, 441, 442, 446, 451, 455, 456, 477, 497, 507, 511, 532, 542, 546, 551, 561, 562, 566, 576, 581, 586, 591, 595, 606, 616, 620, 626, 630, 642, 646, 650
Offset: 1

Views

Author

Jonathan Vos Post, Mar 05 2005

Keywords

Comments

Hyun Kwang Kim asserts that every positive integer can be represented as the sum of no more than 8 pentatope numbers; but in this sequence we are only concerned with sums of nonzero distinct pentatope numbers.

References

  • Conway, J. H. and Guy, R. K. The Book of Numbers. New York: Springer-Verlag, pp. 55-57, 1996.

Crossrefs

Programs

  • Maple
    N:= 1000: # for terms <= N
    ptop:= n -> n*(n+1)*(n+2)*(n+3)/24:
    P:= 1:
    for i from 1 while ptop(i) < N do
      P:= P * (1 + x*y^ptop(i))
    od:
    sort(map(degree,convert(convert(series(coeff(P,x,5),y,N+1),polynom),list)));
    # Robert Israel, Nov 20 2023

Formula

a(n) = Ptop(g) + Ptop(h) + Ptop(i) + Ptop(j) + Ptop(k) for some positive g=/=h=/=i=/=j=/=k and Ptop(n) = binomial(n+3,4).

Extensions

Extended by Ray Chandler, Mar 05 2005

A342865 Irregular table read by rows: T(n,k) is the number of permutations in S_n that have exactly k occurrences of the pattern 1234. 0 <= k <= A000332(n).

Original entry on oeis.org

1, 1, 2, 6, 23, 1, 103, 12, 4, 0, 0, 1, 513, 102, 63, 10, 6, 12, 8, 0, 0, 5, 0, 0, 0, 0, 0, 1, 2761, 770, 665, 196, 146, 116, 142, 46, 10, 72, 32, 24, 0, 13, 0, 12, 18, 0, 0, 10, 0, 0, 0, 0, 0, 6, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
Offset: 0

Views

Author

Peter Kagey, Mar 26 2021

Keywords

Comments

Equivalently the table for the pattern 4321.
First column is A005802.

Examples

			Table begins:
  n\k|       0        1        2        3        4        5        6
  ---+-------------------------------------------------------------------
   0 |       1;
   1 |       1;
   2 |       2;
   3 |       6;
   4 |      23,       1;
   5 |     103,      12,       4,       0,       0,       1;
   6 |     513,     102,      63,      10,       6,      12,       8, ...
   7 |    2761,     770,     665,     196,     146,     116,     142, ...
   8 |   15767,    5545,    5982,    2477,    2148,    1204,    1782, ...
   9 |   94359,   39220,   49748,   25886,   25190,   13188,   19936, ...
  10 |  586590,  276144,  396642,  244233,  260505,  142550,  210663, ...
  11 | 3763290, 1948212, 3089010, 2167834, 2493489, 1476655, 2136586, ...
		

Crossrefs

Analogous for other patterns: A008302 (12), A138159 (321), A263771 (312), A342840 (1342), A342860 (2413), A342861 (1324), A342862 (2143), A342863 (1243), A342864 (1432).

A145919 A000332(n) = a(n)*(3*a(n) - 1)/2.

Original entry on oeis.org

0, 0, 0, 0, 1, 2, -3, 5, 7, -9, 12, 15, -18, 22, 26, -30, 35, 40, -45, 51, 57, -63, 70, 77, -84, 92, 100, -108, 117, 126, -135, 145, 155, -165, 176, 187, -198, 210, 222, -234, 247, 260, -273, 287, 301, -315, 330, 345, -360, 376, 392, -408, 425, 442, -459, 477
Offset: 0

Views

Author

Matthew Vandermast, Oct 28 2008

Keywords

Comments

As the formula in the description shows, all members of A000332 belong to the generalized pentagonal sequence (A001318). A001318 also lists all nonnegative numbers that belong to A145919.

Examples

			a(6) = -3 and A000332(6) = (-3)(-10)/2 = 15.
		

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[(-x^4*(x^4 + 2*x^3 - 3*x^2 + 2*x + 1))/((x - 1)^3*(1 + x^2 + x)^3), {x,0,50}], x] (* G. C. Greubel, Jun 13 2017 *)
    LinearRecurrence[{0,0,3,0,0,-3,0,0,1},{0,0,0,0,1,2,-3,5,7},60] (* Harvey P. Dale, Feb 13 2023 *)
  • PARI
    my(x='x+O('x^50)); concat([0, 0, 0, 0], Vec((-x^4*(x^4 +2*x^3 -3*x^2 +2*x +1))/((x-1)^3*(1+x^2+x)^3))) \\ G. C. Greubel, Jun 13 2017

Formula

a(n+3) = A001840(n) when 3 does not divide n, A001840(n)*-1 otherwise.
After first two zeros, this sequence consists of all values of A001318(n) and A045943(n)*(-1), n>=0, sorted in order of increasing absolute value.
G.f.: (-x^4*(x^4+2*x^3-3*x^2+2*x+1))/((x-1)^3*(1+x^2+x)^3). - Maksym Voznyy (voznyy(AT)mail.ru), Jul 27 2009
a(n) = ((n^2-3*n+1)*(1-4*cos(2*Pi*n/3))+3)/18. - Natalia L. Skirrow, Apr 14 2025

A145920 List of numbers that are both pentagonal (A000326) and binomial coefficients C(n,4) (A000332).

Original entry on oeis.org

0, 1, 5, 35, 70, 210, 330, 715, 1001, 1820, 2380, 3876, 4845, 7315, 8855, 12650, 14950, 20475, 23751, 31465, 35960, 46376, 52360, 66045, 73815, 91390, 101270, 123410, 135751, 163185, 178365, 211876, 230300, 270725, 292825, 341055, 367290, 424270
Offset: 1

Views

Author

Matthew Vandermast, Oct 28 2008

Keywords

Comments

All binomial coefficients C(n,4) belong to the generalized pentagonal sequence (A001318).
Pentagonal numbers of generalized pentagonal number (A001318) index number. - Raphie Frank, Nov 25 2012

Examples

			35, for example, is both A000326(5) and A000332(7).
		

Crossrefs

Cf. A141919, of which this is a subsequence.

Formula

a(n+1) = A000326 (A001318(n)).
Positive values of A000332(n) belong to the sequence if and only if 3 does not divide n. A000332(n) is positive when n>3.
Conjecture: a(n) = a(n-1) + 4a(n-2) - 4a(n-3) - 6a(n-4) + 6a(n-5) + 4a(n-6) - 4a(n-7) - a(n-8) + a(n-9). - R. J. Mathar, Oct 29 2008
Conjecture: G.f.: x^2(1 + 4x + 26x^2 + 19x^3 + 4x^5 + x^6 + 26x^4)/((1+x)^4(1-x)^5). - R. J. Mathar, Oct 29 2008
a(n) = (27x^4 - 18x^3 - 3x^2 + 2x)/8 where x = floor(n/2)*(-1)^n, for n >= 1. - William A. Tedeschi, Aug 16 2010

A104396 Sums of 6 distinct positive pentatope numbers (A000332).

Original entry on oeis.org

252, 336, 392, 427, 447, 456, 457, 461, 512, 547, 567, 577, 581, 596, 621, 631, 651, 661, 665, 677, 687, 707, 712, 717, 721, 732, 742, 746, 752, 756, 761, 772, 776, 786, 796, 816, 826, 830, 841, 852, 872, 881, 882, 886, 897, 907, 916, 917, 921, 932
Offset: 1

Views

Author

Jonathan Vos Post, Mar 05 2005

Keywords

Comments

Pentatope number Ptop(n) = binomial(n+3,4) = n*(n+1)*(n+2)*(n+3)/24.
Hyun Kwang Kim asserts that every positive integer can be represented as the sum of no more than 8 pentatope numbers; but in this sequence we are only concerned with sums of nonzero distinct pentatope numbers.

References

  • Conway, J. H. and Guy, R. K. The Book of Numbers. New York: Springer-Verlag, pp. 55-57, 1996.

Crossrefs

Formula

a(n) = Ptop(f) + Ptop(g) + Ptop(h) + Ptop(i) + Ptop(j) + Ptop(k) for some positive f=/=g=/=h=/=i=/=j=/=k and Ptop(n) = binomial(n+3,4).

Extensions

Extended by Ray Chandler, Mar 05 2005
Showing 1-10 of 396 results. Next