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 15 results. Next

A037444 Number of partitions of n^2 into squares.

Original entry on oeis.org

1, 1, 2, 4, 8, 19, 43, 98, 220, 504, 1116, 2468, 5368, 11592, 24694, 52170, 108963, 225644, 462865, 941528, 1899244, 3801227, 7550473, 14889455, 29159061, 56722410, 109637563, 210605770, 402165159, 763549779, 1441686280, 2707535748, 5058654069, 9404116777
Offset: 0

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Author

Keywords

Comments

Is lim_{n->inf} a(n)^(1/n) > 1? - Paul D. Hanna, Aug 20 2002
The limit above is equal to 1 (see formula by Hardy & Ramanujan for A001156). - Vaclav Kotesovec, Dec 29 2016

Crossrefs

Entries with square index in A001156.
A row or column of the array in A259799.

Programs

  • Haskell
    a037444 n = p (map (^ 2) [1..]) (n^2) where
       p _      0 = 1
       p ks'@(k:ks) m | m < k     = 0
                      | otherwise = p ks' (m - k) + p ks m
    -- Reinhard Zumkeller, Aug 14 2011
  • Maple
    b:= proc(n, i) option remember; `if`(n=0 or i=1, 1,
          b(n, i-1) +`if`(i^2>n, 0, b(n-i^2, i)))
        end:
    a:= n-> b(n^2, n):
    seq(a(n), n=0..40);  # Alois P. Heinz, Apr 15 2013
  • Mathematica
    max=33; se = Series[ Product[1/(1-x^(k^2)), {k, 1, max}], {x, 0, max^2}]; a[n_] := Coefficient[se, x^(n^2)]; a[0] = 1; Table[a[n], {n, 0, max}] (* Jean-François Alcover, Oct 18 2011 *)

Formula

a(n) = A001156(n^2) = coefficient of x^(n^2) in the series expansion of Prod_{k>=1} 1/(1 - x^(k^2)).
a(n) ~ 3^(-1/2) * (4*Pi)^(-7/6) * Zeta(3/2)^(2/3) * n^(-7/3) * exp(2^(-4/3) * 3 * Pi^(1/3) * Zeta(3/2)^(2/3) * n^(2/3)) [Hardy & Ramanujan, 1917, modified from A001156]. - Vaclav Kotesovec, Dec 29 2016

A183953 T(n,k) is the number of strings of numbers x(i=1..n) in 0..k with sum i^2*x(i) equal to k*n^2.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 2, 2, 1, 2, 1, 2, 3, 4, 5, 1, 1, 2, 4, 8, 10, 7, 2, 1, 2, 6, 14, 27, 26, 10, 1, 1, 3, 7, 21, 53, 78, 61, 20, 3, 1, 3, 9, 32, 94, 180, 219, 147, 37, 3, 1, 3, 12, 48, 161, 398, 656, 649, 339, 77, 4, 1, 3, 14, 61, 259, 770, 1613, 2195, 1805, 771, 118, 2, 1, 4, 17
Offset: 1

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Author

R. H. Hardin, Jan 08 2011

Keywords

Comments

T(n,k) is the number of integer lattice points in k*C(n) where C(n) is the polytope in R^n defined by the equation Sum_{1<=i<=n} i^2*x_i = n^2 and the inequalities 0 <= x_i <= 1. The vertices of the polytope have rational coordinates. Thus row n of the table is an Ehrhart quasi-polynomial of degree n-1. - Robert Israel, Jul 10 2019

Examples

			Table starts
.1..1...1....1.....1.....1......1......1.......1.......1.......1........1
.1..1...1....2.....2.....2......2......3.......3.......3.......3........4
.1..2...2....3.....4.....6......7......9......12......14......17.......19
.1..1...4....8....14....21.....32.....48......61......82.....108......139
.2..5..10...27....53....94....161....259.....399.....578.....811.....1120
.1..7..26...78...180...398....770...1387....2330....3738....5772.....8599
.2.10..61..219...656..1613...3539...7099...13225...23247...38938....62599
.1.20.147..649..2195..6301..15601..34847...71509..137520..249799...433038
.3.37.339.1805..7250.23611..65909.163588..369777..775045.1525468..2847243
.3.77.771.4987.23044.85595.268008.737538.1830390.4178324.8894137.17852441
Some solutions for n=5
..4....1....3....0....4....4....0....3....1....3....0....0....0....2....1....0
..3....2....1....0....3....3....0....1....2....1....4....4....0....4....2....4
..3....0....2....1....2....4....4....3....1....4....2....1....0....1....3....4
..2....1....0....1....1....3....4....1....2....2....1....0....0....3....4....3
..1....3....3....3....2....0....0....2....2....1....2....3....4....1....0....0
		

Crossrefs

Column 1 is A030273. A183946 (column 2), A183947 (column 3), A183954 (row 3), A183955 (row 4).

Programs

  • Maple
    A183953rec := proc(n,k,s)
        option remember;
        local c;
        if s < 0 then
            return 0 ;
        elif n = 0 then
            if s =0 then
                return 1;
            else
                return 0 ;
            end if;
        else
            add( procname(n-1,k,s-c*n^2),c=0..k) ;
        end if;
    end proc:
    A183953 := proc(n,k)
        A183953rec(n,k,k*n^2) ;
    end proc:
    seq(seq( A183953(n,d-n),n=1..d-1),d=2..12) ; # R. J. Mathar, Mar 08 2021
  • Mathematica
    r[n_, k_, s_] := r[n, k, s] = Which[s < 0, 0, n == 0, If[s == 0, 1, 0], True, Sum[r[n-1, k, s-c*n^2], {c, 0, k}]];
    T[n_, k_] := r[n, k, k*n^2];
    Table[Table[T[n, d-n], {n, 1, d-1}], {d, 2, 14}] // Flatten (* Jean-François Alcover, Jul 22 2022, after R. J. Mathar *)

A184240 T(n,k)=Number of strings of numbers x(i=1..n) in 0..k with sum i^2*x(i)^2 equal to n^2*k^2.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 5, 4, 2, 1, 1, 2, 2, 3, 5, 4, 1, 1, 1, 1, 2, 15, 15, 41, 7, 3, 1, 1, 1, 2, 11, 24, 31, 36, 19, 3, 1, 1, 3, 1, 30, 43, 213, 119, 199, 47, 4, 1, 1, 2, 5, 5, 47, 176, 356, 555, 420, 71, 2, 1, 1, 2, 3, 79, 88, 706, 962, 2531, 2138
Offset: 1

Views

Author

R. H. Hardin Jan 10 2011

Keywords

Comments

Table starts
.1..1...1....1....1.....1.....1......1......1.......1.......1.......1.......1
.1..1...1....1....1.....1.....1......1......1.......1.......1.......1.......2
.1..1...2....1....1.....2.....1......1......3.......2.......2.......2.......2
.1..1...1....1....2.....2.....2......1......5.......3.......3.......2.......4
.2..2...5....3...15....11....30......5.....79......30......99......30.....129
.1..4...5...15...24....43....47.....88....155.....251.....249.....349.....507
.2..4..41...31..213...176...706....571...2355....1508....5431....3445...10802
.1..7..36..119..356...962..2108...3719...6688...13801...22721...31805...53339
.3.19.199..555.2531..5920.19178..32608..85718..133989..284012..450961..850956
.3.47.420.2138.9710.32442.97714.229978.570177.1186420.2444060.4476795.8278231

Examples

			Some solutions for n=6 k=5
..4....2....0....0....0....4....0....4....4....0....0....0....0....0....0....0
..2....4....2....5....4....5....4....0....4....2....5....5....3....4....0....4
..2....0....4....0....4....4....4....4....4....4....4....0....4....0....0....2
..4....4....1....4....1....2....4....2....0....2....4....5....3....5....0....5
..0....0....4....4....2....0....4....2....2....2....4....4....0....4....0....4
..4....4....3....2....4....4....1....4....4....4....0....0....4....1....5....0
		

Crossrefs

Column 1 is A030273

A184318 T(n,k) = number of strings of numbers x(i=1..n) in 0..k with sum i^2*x(i)^3 equal to n^2*k^3.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 2, 2, 2, 1, 1, 1, 1, 2, 2, 3, 1, 1, 1, 1, 2, 3, 5, 6, 8, 3, 1, 1, 1, 1, 3, 5, 16, 30, 12, 3, 1, 1, 1, 2, 3, 11, 38, 68, 69, 21, 4, 1, 1, 1, 1, 2, 7, 50, 126, 244, 230, 47, 2, 1, 1, 1, 2, 3, 18, 69, 319, 763, 1106, 662, 117, 7, 1, 1
Offset: 1

Views

Author

R. H. Hardin, Jan 10 2011

Keywords

Comments

Table starts
.1..1...1....1....1....1.....1.....1......1......1......1......1.......1
.1..1...1....1....1....1.....1.....1......1......1......1......1.......1
.1..1...1....1....1....1.....1.....1......1......1......1......1.......1
.1..2...1....2....1....2.....1.....2......1......2......1......2.......1
.2..2...2....2....3....3.....3.....2......3......4......4......4.......2
.1..2...2....5....5...11.....7....18.....15.....26.....37.....47......50
.2..3...6...16...38...50....69...139....188....284....336....550.....608
.1..8..30...68..126..319...574..1056...1637...2680...3831...6128....8009
.3.12..69..244..763.1602..3336..7826..12904..23558..36719..62495...93074
.3.21.230.1106.3133.9343.23562.54515.104508.205011.373576.655153.1053794

Examples

			All solutions for n=6 k=5
..2....0....0....0....0
..5....1....0....3....2
..2....4....0....3....3
..1....1....0....4....2
..4....4....0....5....5
..4....4....5....0....3
		

Crossrefs

Column 1 is A030273.

A288126 Number of partitions of n-th triangular number (A000217) into distinct triangular parts.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 2, 3, 2, 4, 7, 6, 4, 14, 15, 19, 31, 28, 43, 57, 80, 103, 127, 181, 234, 295, 398, 539, 663, 888, 1178, 1419, 1959, 2519, 3102, 4201, 5282, 6510, 8717, 11162, 13557, 18108, 22965, 28206, 36860, 46350, 58060, 73857, 93541, 117058, 147376, 186158, 232949, 292798, 365639
Offset: 0

Views

Author

Ilya Gutkovskiy, Jun 05 2017

Keywords

Examples

			a(4) = 2 because 4th triangular number is 10 and we have [10], [6, 3, 1].
		

Crossrefs

Programs

  • Maple
    N:= 100:
    G:= mul(1+x^(k*(k+1)/2),k=1..N):
    seq(coeff(G,x,n*(n+1)/2),n=0..N); # Robert Israel, Jun 06 2017
  • Mathematica
    Table[SeriesCoefficient[Product[1 + x^(k (k + 1)/2), {k, 1, n}], {x, 0, n (n + 1)/2}], {n, 0, 54}]

Formula

a(n) = [x^(n*(n+1)/2)] Product_{k>=1} (1 + x^(k(k+1)/2)).
a(n) = A024940(A000217(n)).

A298857 Number of partitions of the n-th tetrahedral number into distinct tetrahedral numbers.

Original entry on oeis.org

1, 1, 1, 1, 1, 2, 2, 1, 2, 3, 2, 5, 5, 10, 12, 17, 15, 22, 30, 56, 65, 72, 92, 172, 219, 299, 368, 478, 810, 1055, 1508, 1778, 2277, 3815, 5214, 7103, 8615, 11614, 18079, 24428, 33704, 42877, 56639, 85597, 116984, 159179, 199356, 268965, 400612, 545674, 740356, 950897, 1261597, 1842307
Offset: 0

Views

Author

Ilya Gutkovskiy, Jan 27 2018

Keywords

Examples

			a(5) = 2 because fifth tetrahedral number is 35 and we have [35] and [20, 10, 4, 1].
		

Crossrefs

Programs

  • Mathematica
    Table[SeriesCoefficient[Product[1 + x^(k (k + 1) (k + 2)/6), {k, 1, n}], {x, 0, n (n + 1) (n + 2)/6}], {n, 0, 53}]

Formula

a(n) = [x^A000292(n)] Product_{k>=1} (1 + x^A000292(k)).
a(n) = A279278(A000292(n)).

A337763 Number of partitions of the n-th n-gonal number into distinct n-gonal numbers.

Original entry on oeis.org

1, 1, 1, 1, 1, 2, 2, 1, 1, 1, 2, 1, 1, 4, 4, 2, 2, 4, 7, 8, 5, 6, 14, 6, 13, 23, 16, 19, 32, 34, 48, 56, 62, 73, 137, 126, 203, 257, 256, 409, 503, 612, 794, 1097, 1203, 1737, 2141, 2773, 3322, 4527, 5087, 7497, 8214, 11238, 12598
Offset: 0

Views

Author

Ilya Gutkovskiy, Sep 19 2020

Keywords

Examples

			a(5) = 2 because 5th pentagonal number is 35 and we have [35] and [22, 12, 1].
		

Crossrefs

Formula

a(n) = [x^p(n,n)] Product_{k=1..n} (1 + x^p(n,k)), where p(n,k) = k * (k * (n - 2) - n + 4) / 2 is the k-th n-gonal number.

A298934 Number of partitions of n^2 into distinct cubes.

Original entry on oeis.org

1, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 2, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 3, 1, 0, 0, 0, 0, 0, 0, 3, 3, 1, 0, 3, 0, 2, 4, 0, 0, 1, 0, 0, 2, 3, 1, 1, 0, 6, 3, 6, 1, 6, 0, 3, 9, 0, 6, 6, 7, 0, 10, 3, 3, 6, 0, 8, 6, 13, 2, 10, 9, 10, 19, 2, 14, 21, 7, 2, 25
Offset: 0

Views

Author

Ilya Gutkovskiy, Jan 29 2018

Keywords

Examples

			a(15) = 2 because we have [216, 8, 1] and [125, 64, 27, 8, 1].
		

Crossrefs

Programs

  • Maple
    b:= proc(n, i) option remember; `if`(n=0, 1,
          `if`(n>i^2*(i+1)^2/4, 0, b(n, i-1)+
          `if`(i^3>n, 0, b(n-i^3, i-1))))
        end:
    a:= n-> b(n^2, n):
    seq(a(n), n=0..100);  # Alois P. Heinz, Jan 29 2018
  • Mathematica
    Table[SeriesCoefficient[Product[1 + x^k^3, {k, 1, Floor[n^(2/3) + 1]}], {x, 0, n^2}], {n, 0, 84}]

Formula

a(n) = [x^(n^2)] Product_{k>=1} (1 + x^(k^3)).
a(n) = A279329(A000290(n)).

A298935 Number of partitions of n^3 into distinct squares.

Original entry on oeis.org

1, 1, 0, 0, 1, 5, 8, 40, 96, 297, 1269, 3456, 12839, 46691, 153111, 577167, 2054576, 7602937, 29000337, 110645967, 418889453, 1580667760, 6058528796, 23121913246, 89793473393, 350029321425, 1359919742613, 5340642744919, 20948242218543, 82505892314268
Offset: 0

Views

Author

Ilya Gutkovskiy, Jan 29 2018

Keywords

Examples

			a(5) = 5 because we have [121, 4], [100, 25], [100, 16, 9], [64, 36, 25] and [64, 36, 16, 9].
		

Crossrefs

Programs

  • Mathematica
    Table[SeriesCoefficient[Product[1 + x^k^2, {k, 1, Floor[n^(3/2) + 1]}], {x, 0, n^3}], {n, 0, 29}]

Formula

a(n) = [x^(n^3)] Product_{k>=1} (1 + x^(k^2)).
a(n) = A033461(A000578(n)).

A298642 Number of partitions of n^2 into distinct squares > 1.

Original entry on oeis.org

1, 0, 1, 1, 1, 2, 1, 2, 1, 2, 2, 2, 1, 5, 2, 10, 4, 12, 12, 11, 19, 23, 43, 50, 55, 78, 120, 126, 234, 207, 407, 385, 701, 712, 1090, 1231, 1850, 2102, 3054, 3385, 4988, 5584, 7985, 9746, 12205, 15737, 18968, 25157, 30927, 39043, 47708, 61915, 74592, 99554
Offset: 0

Views

Author

Ilya Gutkovskiy, Jan 24 2018

Keywords

Examples

			a(5) = 2 because we have [25] and [16, 9].
		

Crossrefs

Formula

a(n) = [x^(n^2)] Product_{k>=2} (1 + x^(k^2)).
a(n) = A280129(A000290(n)).
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