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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A372890 Sum of binary ranks of all integer partitions of n, where the binary rank of a partition y is given by Sum_i 2^(y_i-1).

Original entry on oeis.org

0, 1, 4, 10, 25, 52, 115, 228, 471, 931, 1871, 3687, 7373, 14572, 29049, 57694, 115058, 229101, 457392, 912469, 1822945, 3640998, 7277426, 14544436, 29079423, 58137188, 116254386, 232465342, 464889800, 929691662, 1859302291, 3718428513, 7436694889, 14873042016
Offset: 0

Views

Author

Gus Wiseman, May 23 2024

Keywords

Examples

			The partitions of 4 are (4), (3,1), (2,2), (2,1,1), (1,1,1,1), with respective binary ranks 8, 5, 4, 4, 4 with sum 25, so a(4) = 25.
		

Crossrefs

For Heinz number (not binary rank) we have A145519, row sums of A215366.
For Heinz number the strict version is A147655, row sums of A246867.
The strict version is A372888, row sums of A118462.
A005117 gives Heinz numbers of strict integer partitions.
A048675 gives binary rank of prime indices, distinct A087207.
A061395 gives greatest prime index, least A055396.
A118457 lists strict partitions in Mathematica order.
A277905 groups all positive integers by binary rank of prime indices.
Binary indices (A048793):
- length A000120, complement A023416
- min A001511, opposite A000012
- max A029837 or A070939, opposite A070940
- sum A029931, product A096111
- reverse A272020
- complement A368494, sum A359400
- opposite complement A371571, sum A359359
- opposite A371572, sum A230877

Programs

  • Maple
    b:= proc(n, i) option remember; `if`(n=0 or i=1, [1, n],
          b(n, i-1)+(p->[0, p[1]*2^(i-1)]+p)(b(n-i, min(n-i, i))))
        end:
    a:= n-> b(n$2)[2]:
    seq(a(n), n=0..33);  # Alois P. Heinz, May 23 2024
  • Mathematica
    Table[Total[Total[2^(#-1)]&/@IntegerPartitions[n]],{n,0,10}]

Formula

From Alois P. Heinz, May 23 2024: (Start)
a(n) = Sum_{k=1..n} 2^(k-1) * A066633(n,k).
a(n) mod 2 = A365410(n-1) for n>=1. (End)

A325505 Heinz number of the set of Heinz numbers of all strict integer partitions of n.

Original entry on oeis.org

2, 3, 5, 143, 493, 62651, 26718511, 22017033127, 44220524211551, 52289759420183033963, 546407750301194131199484983, 8362548333129019658779663581495109, 1828111016191440393570169991636207115709029581, 1059934964500839879758659437301868941873808925011368355891
Offset: 0

Views

Author

Gus Wiseman, May 07 2019

Keywords

Comments

The Heinz number of a set or sequence (y_1,...,y_k) is prime(y_1)*...*prime(y_k).
Also Heinz numbers of rows of A246867 (squarefree numbers arranged by sum of prime indices A056239).

Examples

			The strict integer partitions of 5 are {(5), (4,1), (3,2)}, with Heinz numbers {11,14,15}, with Heinz number prime(11)*prime(14)*prime(15) = 62651, so a(6) = 62651.
The sequence of terms together with their prime indices begins:
                            2: {1}
                            3: {2}
                            5: {3}
                          143: {5,6}
                          493: {7,10}
                        62651: {11,14,15}
                     26718511: {13,21,22,30}
                  22017033127: {17,26,33,35,42}
               44220524211551: {19,34,39,55,66,70}
         52289759420183033963: {23,38,51,65,77,78,105,110}
  546407750301194131199484983: {29,46,57,85,91,102,130,154,165,210}
		

Crossrefs

Programs

  • Mathematica
    Table[Times@@Prime/@(Times@@Prime/@#&/@Select[IntegerPartitions[n],UnsameQ@@#&]),{n,7}]

Formula

a(n) = Product_{i = 1..A000009(n)} prime(A246867(n,i)).
A001221(a(n)) = A001222(a(n)) = A000009(n).
A056239(a(n)) = A147655(n).
A003963(a(n)) = A325506(n).

A372888 Sum of binary ranks of all strict integer partitions of n, where the binary rank of a partition y is given by Sum_i 2^(y_i-1).

Original entry on oeis.org

0, 1, 2, 7, 13, 31, 66, 138, 279, 581, 1173, 2375, 4783, 9630, 19316, 38802, 77689, 155673, 311639, 623845, 1248179, 2497719, 4996387, 9995304, 19992908, 39990902, 79986136, 159983241, 319975073, 639971495, 1279962115, 2559966847, 5119970499, 10240030209
Offset: 0

Views

Author

Gus Wiseman, May 23 2024

Keywords

Examples

			The strict partitions of 6 are (6), (5,1), (4,2), (3,2,1), with respective binary ranks 32, 17, 10, 7 with sum 66, so a(6) = 66.
		

Crossrefs

Row sums of A118462 (binary ranks of strict partitions).
For Heinz number the non-strict version is A145519, row sums of A215366.
For Heinz number (not binary rank) we have A147655, row sums of A246867.
The non-strict version is A372890.
A000009 counts strict partitions, ranks A005117.
A048675 gives binary rank of prime indices, distinct A087207.
A277905 groups all positive integers by binary rank of prime indices.
Binary indices (A048793):
- length A000120, complement A023416
- min A001511, opposite A000012
- max A029837 or A070939, opposite A070940
- sum A029931, product A096111
- reverse A272020
- complement A368494, sum A359400
- opposite A371572, sum A230877
- opposite complement A371571, sum A359359

Programs

  • Maple
    b:= proc(n, i) option remember; `if`(i*(i+1)/2 [0, p[1]*2^(i-1)]
              +p)(b(n-i, min(n-i, i-1)))))
        end:
    a:= n-> b(n$2)[2]:
    seq(a(n), n=0..33);  # Alois P. Heinz, May 23 2024
  • Mathematica
    Table[Total[Total[2^(#-1)]& /@ Select[IntegerPartitions[n],UnsameQ@@#&]],{n,0,10}]

Formula

a(n) = Sum_{k=1..n} 2^(k-1) * A015716(n,k). - Alois P. Heinz, May 24 2024

A147880 Expansion of Product_{k > 0} (1 + A005229(k)*x^k).

Original entry on oeis.org

1, 1, 1, 3, 5, 8, 12, 21, 30, 50, 75, 110, 169, 249, 361, 539, 757, 1076, 1583, 2207, 3121, 4415, 6184, 8468, 11775, 16274, 22314, 30601, 41745, 56412, 77008, 103507, 138383, 186928, 249855, 333375, 443898, 588402, 778276, 1031126, 1356945, 1780645
Offset: 0

Views

Author

Roger L. Bagula, Nov 16 2008

Keywords

Examples

			From _Petros Hadjicostas_, Apr 10 2020: (Start)
Let f(m) = A005229(m). Using the strict partitions of each n (see A000009), we get
a(1) = f(1) = 1,
a(2) = f(2) = 1,
a(3) = f(3) + f(1)*f(2) = 2 + 1*1 = 3,
a(4) = f(4) + f(1)*f(3) = 3 + 1*2 = 5,
a(5) = f(5) + f(1)*f(4) + f(2)*f(3) = 3 + 1*3 + 1*2 = 8,
a(6) = f(6) + f(1)*f(5) + f(2)*f(4) + f(1)*f(2)*f(3) = 4 + 1*3 + 1*3 + 1*1*2 = 12,
a(7) = f(7) + f(1)*f(6) + f(2)*f(5) + f(3)*f(4) + f(1)*f(2)*f(4) = 5 + 1*4 + 1*3 + 2*3 + 1*1*3 = 21. (End)
		

Crossrefs

Programs

  • Mathematica
    (*A005229*) f[n_Integer?Positive] := f[n] = f[ f[n - 2]] + f[n - f[n - 2]]; f[0] = 0; f[1] = f[2] = 1;
    P[x_, n_] := P[x, n] = Product[1 + f[m] *x^m, {m, 0, n}];
    Take[CoefficientList[P[x, 45], x], 45] (* Program simplified by Petros Hadjicostas, Apr 13 2020 *)
  • PARI
    \\ here B(n) is A005229 as vector.
    B(n)={my(a=vector(n, i, 1)); for(n=3, n, a[n] = a[a[n-2]] + a[n-a[n-2]]); a}
    seq(n)={my(v=B(n)); Vec(prod(k=1, n, 1 + v[k]*x^k + O(x*x^n)))} \\ Andrew Howroyd, Apr 10 2020

Formula

G.f.: Product_{k > 0} (1 + A005229(k)*x^k).
a(n) = Sum_{(b_1,...,b_n)} f(1)^b_1 * f(2)^b_2 * ... * f(n)^b_n, where f(m) = A005229(m), and the sum is taken over all lists (b_1,...,b_n) with b_j in {0,1} and Sum_{j=1..n} j*b_j = n.

Extensions

Various sections edited by Joerg Arndt and Petros Hadjicostas, Apr 10 2020

A147871 Expansion of Product_{k > 0} (1 + A147665(k)*x^k).

Original entry on oeis.org

1, 1, 1, 3, 4, 7, 10, 15, 24, 37, 49, 73, 105, 142, 208, 294, 391, 538, 752, 988, 1359, 1812, 2410, 3232, 4270, 5598, 7454, 9721, 12639, 16625, 21445, 27649, 35793, 46235, 59141, 76215, 96975, 123262, 157671, 199625, 252591, 319792, 403262, 507682
Offset: 0

Views

Author

Roger L. Bagula, Nov 16 2008

Keywords

Examples

			From _Petros Hadjicostas_, Apr 11 2020: (Start)
Let f(m) = A147665(m). Using the strict partitions of each n (see A000009), we get
a(1) = f(1) = 1,
a(2) = f(2) = 1,
a(3) = f(3) + f(1)*f(2) = 2 + 1*1 = 3,
a(4) = f(4) + f(1)*f(3) = 2 + 1*2 = 4,
a(5) = f(5) + f(1)*f(4) + f(2)*f(3) = 3 + 1*2 + 1*2 = 7,
a(6) = f(6) + f(1)*f(5) + f(2)*f(4) + f(1)*f(2)*f(3) = 3 + 1*3 + 1*2 + 1*1*2 = 10,
a(7) = f(7) + f(1)*f(6) + f(2)*f(5) + f(3)*f(4) + f(1)*f(2)*f(4) = 3 + 1*3 + 1*3 + 2*2 + 1*1*2 = 15. (End)
		

Crossrefs

Programs

  • Mathematica
    (*A147665*) f[0] = 0; f[1] = 1; f[2] = 1; f[n_] := f[n] = f[f[n - 1]] + If[Mod[ n, 3] == 0, f[f[n/3]], If[Mod[n, 3] == 1, f[f[(n - 1)/3]], f[n - f[(n - 2)/3]]]];
    P[x_, n_] := P[x, n] = Product[1 + f[m]*x^m, {m, 0, n}];
    Take[CoefficientList[P[x, 45], x], 45] (* Program simplified by Petros Hadjicostas, Apr 13 2020 *)

Formula

a(n) = [x^n] Product_{k > 0} (1 + A147665(k)*x^k).
a(n) = Sum_{(b_1,...,b_n)} f(1)^b_1 * f(2)^b_2 * ... * f(n)^b_n, where f(m) = A147665(m), and the sum is taken over all lists (b_1,...,b_n) with b_j in {0,1} and Sum_{j=1..n} j*b_j = n. - Petros Hadjicostas, Apr 11 2020

Extensions

Various sections edited by Petros Hadjicostas, Apr 11 2020

A147869 Expansion of Product_{k>0} (1 + A004001(k)*x^k).

Original entry on oeis.org

1, 1, 1, 3, 4, 7, 11, 17, 25, 41, 59, 86, 125, 180, 263, 382, 536, 738, 1073, 1466, 2028, 2841, 3889, 5275, 7211, 9800, 13249, 17860, 23948, 31921, 42864, 56802, 75115, 99788, 131239, 172870, 226789, 296404, 386745, 504939, 655227, 849628, 1101270
Offset: 0

Views

Author

Roger L. Bagula, Nov 16 2008

Keywords

Examples

			From _Petros Hadjicostas_, Apr 11 2020: (Start)
Let f(m) = A004001(m). Using the strict partitions of each n (see A000009), we get
a(1) = f(1) = 1,
a(2) = f(2) = 1,
a(3) = f(3) + f(1)*f(2) = 2 + 1*1 = 3,
a(4) = f(4) + f(1)*f(3) = 2 + 1*2 = 4,
a(5) = f(5) + f(1)*f(4) + f(2)*f(3) = 3 + 1*2 + 1*2 = 7,
a(6) = f(6) + f(1)*f(5) + f(2)*f(4) + f(1)*f(2)*f(3) = 4 + 1*3 + 1*2 + 1*1*2 = 11,
a(7) = f(7) + f(1)*f(6) + f(2)*f(5) + f(3)*f(4) + f(1)*f(2)*f(4) = 4 + 1*4 + 1*3 + 2*2 + 1*1*2 = 17. (End)
		

Crossrefs

Programs

  • Mathematica
    f[0] = 0; f[1] = 1; f[2] = 1; f[n_] := f[n] = f[f[n - 1]] + f[n - f[n - 1]];
    P[x_, n_] := P[x, n] = Product[1 + f[m]*x^m, {m, 0, n}];
    Take[CoefficientList[P[x, 45], x], 45]

Formula

a(n) = [x^n] Product_{k > 0} (1 + A004001(k)*x^k).
a(n) = Sum_{(b_1,...,b_n)} f(1)^b_1 * f(2)^b_2 * ... * f(n)^b_n, where f(m) = A004001(m), and the sum is taken over all lists (b_1,...,b_n) with b_j in {0,1} and Sum_{j=1..n} j*b_j = n. - Petros Hadjicostas, Apr 11 2020

Extensions

Various sections edited by Petros Hadjicostas, Apr 11 2020

A325515 Sum of sums of omegas of the parts over all strict integer partitions of n.

Original entry on oeis.org

0, 0, 1, 2, 3, 5, 8, 11, 14, 22, 29, 37, 50, 63, 81, 106, 129, 160, 203, 246, 303, 373, 449, 541, 654, 782, 932, 1116, 1322, 1559, 1848, 2167, 2537, 2978, 3470, 4041, 4706, 5449, 6303, 7291, 8402, 9665, 11117, 12744, 14592, 16708, 19062, 21730, 24757, 28141
Offset: 0

Views

Author

Gus Wiseman, May 07 2019

Keywords

Comments

Also omega of the product of products of parts over all strict integer partitions of n.
The omega of n is A001222(n), the number of prime factors of n counted with multiplicity.

Crossrefs

Programs

  • Mathematica
    Table[Sum[Total[PrimeOmega/@s],{s,Select[IntegerPartitions[n],UnsameQ@@#&]}],{n,0,30}]

Formula

a(n) = A001222(A325504(n)).

A147953 Expansion of Product_{k > 0} (1 + f(k)*x^k), where f(n) = A147952(n).

Original entry on oeis.org

1, 1, 1, 3, 4, 7, 9, 14, 22, 32, 43, 61, 89, 118, 167, 235, 312, 417, 572, 748, 1006, 1326, 1744, 2283, 2982, 3878, 5048, 6518, 8355, 10786, 13727, 17436, 22173, 28250, 35561, 45008, 56651, 70818, 88992, 111280, 138431, 172284, 214019, 265166, 328127
Offset: 0

Views

Author

Roger L. Bagula, Nov 17 2008

Keywords

Crossrefs

Programs

  • Mathematica
    f[0] = 0; f[1] = 1; f[2] = 1;
    f[n_] := f[n] = f[f[n - 2]] + If[Mod[n, 3] == 0,f[f[n/3]], If[Mod[n, 3] == 1, f[f[(n - 1)/3]], f[n - f[(n - 2)/3]]]];
    P[x_, n_] := P[x, n] = Product[1 + f[m] x^m, {m, 0, n}];
    Take[CoefficientList[P[x, 45], x],45]
    (* Program edited and corrected by Petros Hadjicostas, Apr 12 2020 *)

Formula

a(n) = [x^n] Product_{k > 0} (1 + f(k)*x^k), where f(1) = f(2) = 1, and for m >= 3, f(m) = f(f(m-2)) + r(m), where r(m) = f(f(floor(m/3)) when m == 0 or 1 (mod 3) and = f(m - f(floor(m/3))) when m == 2 (mod 3).

Extensions

Various sections edited by Petros Hadjicostas, Apr 12 2020

A305881 Expansion of Product_{k>=1} 1/(1 + prime(k)*x^k).

Original entry on oeis.org

1, -2, 1, -7, 16, -28, 62, -118, 303, -630, 1152, -2426, 5315, -10718, 20482, -43449, 91111, -179254, 358910, -727829, 1484601, -2995681, 5924606, -11935441, 24382120, -48702245, 96682698, -195063604, 392983826, -784903199, 1569490057, -3146479152, 6317124649, -12652202092
Offset: 0

Views

Author

Ilya Gutkovskiy, Jun 13 2018

Keywords

Comments

Convolution inverse of A147655.

Crossrefs

Programs

  • Maple
    b:= proc(n, i) option remember; `if`(n=0, 1, `if`(i<1, 0,
          b(n, i-1) +`if`(i>n, 0, b(n-i, i-1)*ithprime(i))))
        end:
    a:= proc(n) option remember; `if`(n=0, 1,
          -add(b(n-i$2)*a(i$2), i=0..n-1))
        end:
    seq(a(n), n=0..40);  # Alois P. Heinz, Jun 13 2018
  • Mathematica
    nmax = 33; CoefficientList[Series[Product[1/(1 + Prime[k] x^k), {k, 1, nmax}], {x, 0, nmax}], x]
    nmax = 33; CoefficientList[Series[Exp[Sum[Sum[(-1)^k Prime[j]^k x^(j k)/k, {j, 1, nmax}], {k, 1, nmax}]], {x, 0, nmax}], x]
    a[n_] := a[n] = If[n == 0, 1, Sum[Sum[d (-Prime[d])^(k/d), {d, Divisors[k]}] a[n - k], {k, 1, n}]/n]; Table[a[n], {n, 0, 33}]

Formula

G.f.: exp(Sum_{k>=1} Sum_{j>=1} (-1)^k*prime(j)^k*x^(j*k)/k).

A147955 Expansion of Product_{k >= 0} (1 + A147954(k)*x^k).

Original entry on oeis.org

1, 1, 1, 3, 4, 7, 10, 15, 22, 34, 46, 65, 93, 123, 175, 245, 324, 425, 592, 764, 1015, 1352, 1750, 2266, 2931, 3793, 4897, 6259, 7930, 10080, 12788, 16047, 20176, 25482, 31641, 39630, 49306, 60932, 75552, 93432, 114597, 141013, 173259, 211595, 258933, 316375, 384359, 466927, 566443
Offset: 0

Views

Author

Roger L. Bagula, Nov 17 2008

Keywords

Examples

			From _Petros Hadjicostas_, Apr 21 2020: (Start)
Let f(m) = A147954(m). Using the strict partitions of n (see A000009), we get:
a(1) = f(1) = 1,
a(2) = f(2) = 1,
a(3) = f(3) + f(1)*f(2) = 2 + 1*1 = 3,
a(4) = f(4) + f(1)*f(3) = 2 + 1*2 = 4,
a(5) = f(5) + f(1)*f(4) + f(2)*f(3) = 3 + 1*2 + 1*2 = 7,
a(6) = f(6) + f(1)*f(5) + f(2)*f(4) + f(1)*f(2)*f(3) = 3 + 1*3 + 1*2 + 1*1*2 = 10,
a(7) = f(7) + f(1)*f(6) + f(2)*f(5) + f(3)*f(4) + f(1)*f(2)*f(4) = 3 + 1*3 + 1*3 + 2*2 + 1*1*2 = 15. (End)
		

Crossrefs

Programs

  • Maple
    f := proc(n) local v; option remember;
    if n = 0 then v := 0; end if;
    if n = 1 or n = 2 then v := 1; end if;
    if 3 <= n and n <= 5 then v := f(f(n - 1)) + f(n - f(n - 1)); end if;
    if 6 <= n and 5 <> n mod 6 then v := f(f(n - 1)) + f(f(floor(n/6))); end if;
    if 6 <= n and 5 = n mod 6 then v := f(f(n - 1)) + f(n - f(floor(n/6))); end if; v; end proc; # this gives sequence A147954
    b:= proc(n, i) option remember; `if`(n=0, 1, `if`(i<1, 0,
          b(n, i-1) +`if`(i>n, 0, b(n-i, i-1)*f(i))))
        end:
    a:= n-> b(n$2):
    seq(a(n), n=0..50); # Petros Hadjicostas, Apr 21 2020 (using Alois P. Heinz's program from A147655)
  • Mathematica
    f[0] = 0; f[1] = 1; f[2] = 1;
    f[n_] := f[n] =
       f[f[n - 1]] +
        If[n < 6, f[n - f[n - 1]],
         If[Mod[n, 6] == 0, f[f[n/6]],
          If[Mod[n, 6] == 1, f[f[(n - 1)/6]],
           If[Mod[n, 6] == 2, f[f[(n - 2)/6]],
            If[Mod[n, 6] == 3, f[f[(n - 3)/6]],
             If[Mod[n, 6] == 4, f[f[(n - 4)/6]], f[n - f[(n - 5)/6]]]]]]]];
    P[x_, n_] := P[x, n] = Product[1 + f[m]*x^m, {m, 0, n}];
    Take[CoefficientList[P[x, 45], x], 45]

Formula

a(n) = [x^n] Product_{k >= 0} (1 + A147954(k)*x^k).
a(n) = Sum_{(b_1,...,b_n)} f(1)^b_1 * f(2)^b_2 * ... * f(n)^b_n, where f(m) = A147954(m), and the sum is taken over all lists (b_1,...,b_n) with b_j in {0,1} and Sum_{j=1..n} j*b_j = n. - Petros Hadjicostas, Apr 21 2020

Extensions

Name, data, and Mathematica program edited and corrected by Petros Hadjicostas, Apr 21 2020
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