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 1-7 of 7 results.

A084993 Total number of parts in all partitions of n into prime parts.

Original entry on oeis.org

0, 1, 1, 2, 3, 5, 6, 9, 12, 16, 20, 27, 33, 42, 53, 64, 80, 96, 117, 141, 169, 201, 239, 282, 333, 390, 456, 532, 617, 715, 826, 951, 1094, 1253, 1435, 1636, 1864, 2119, 2404, 2723, 3078, 3473, 3915, 4403, 4947, 5549, 6215, 6952, 7767, 8665, 9656, 10748
Offset: 1

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Author

Vladeta Jovovic, Jul 17 2003

Keywords

Examples

			Partitions of 9 into primes are 2+2+2+3=3+3+3=2+2+5=2+7; thus a(9)=4+3+3+2=12.
		

Crossrefs

Programs

  • Maple
    g:=sum(x^ithprime(j)/(1-x^ithprime(j)),j=1..20)/product(1-x^ithprime(j),j=1..20): gser:=series(g,x=0,60): seq(coeff(gser,x^n),n=1..57); # Emeric Deutsch, Mar 07 2006
    # second Maple program:
    with(numtheory):
    b:= proc(n, i) option remember; local g;
          if n=0 then [1, 0]
        elif i<1 then [0, 0]
        elif i=1 then `if`(irem(n, 2)=0, [1, n/2], [0, 0])
        else g:= `if`(ithprime(i)>n, [0$2], b(n-ithprime(i), i));
             b(n, i-1) +g +[0, g[1]]
          fi
        end:
    a:= n-> b(n, pi(n))[2]:
    seq(a(n), n=1..60);  # Alois P. Heinz, Oct 30 2012
  • Mathematica
    nn=40;a=Product[1/(1-y x^i),{i,Table[Prime[n],{n,1,nn}]}];Drop[CoefficientList[Series[D[a,y]/.y->1,{x,0,nn}],x],1]  (* Geoffrey Critzer, Oct 30 2012 *)
    b[n_, i_] := b[n, i] = Module[{g}, Which[n == 0, {1, 0}, i < 1, {0, 0}, i == 1, If[EvenQ[n], {1, n/2}, {0, 0}], True, g = If[Prime[i] > n, {0, 0}, b[n - Prime[i], i]]; b[n, i - 1] + g + {0, g[[1]]}]];
    a[n_] := b[n, PrimePi[n]][[2]];
    Array[a, 52] (* Jean-François Alcover, Dec 30 2017, after Alois P. Heinz *)
    Table[Length[Flatten[Select[IntegerPartitions[n],AllTrue[#,PrimeQ]&]]],{n,60}] (* Harvey P. Dale, Jul 11 2023 *)
  • PARI
    sumparts(n, pred)={sum(k=1, n, 1/(1-pred(k)*x^k) - 1 + O(x*x^n))/prod(k=1, n, 1-pred(k)*x^k + O(x*x^n))}
    {my(n=60); Vec(sumparts(n, isprime), -n)} \\ Andrew Howroyd, Dec 28 2017

Formula

G.f.: sum(x^p(j)/(1-x^p(j)),j=1..infinity)/product(1-x^p(j), j=1..infinity), where p(j) is the j-th prime. - Emeric Deutsch, Mar 07 2006

A281477 Expansion of Sum_{k>=1} x^(prime(k)^2)/(1 + x^(prime(k)^2)) * Product_{k>=1} (1 + x^(prime(k)^2)).

Original entry on oeis.org

0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 2, 0, 0, 0, 0, 2, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 2, 0, 0, 0, 0, 2, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 3, 0, 0, 0, 0, 3, 0, 0, 0, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
Offset: 1

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Author

Ilya Gutkovskiy, Jan 27 2017

Keywords

Comments

Total number of parts in all partitions of n into distinct squares of primes (A001248).

Examples

			a(38) = 3 because we have [25, 9, 4].
		

Crossrefs

Programs

  • Maple
    Primes:= select(isprime, [$1..20]):
    g:= add(x^(p^2)/(1+x^(p^2)),p=Primes)*mul(1+x^(p^2),p=Primes):
    S:= series(g, x, 20^2+1):
    seq(coeff(S,x,n),n=1..20^2); # Robert Israel, Feb 08 2017
  • Mathematica
    nmax = 125; Rest[CoefficientList[Series[Sum[x^Prime[k]^2/(1 + x^Prime[k]^2), {k, 1, nmax}] Product[1 + x^Prime[k]^2, {k, 1, nmax}], {x, 0, nmax}], x]]

Formula

G.f.: Sum_{k>=1} x^(prime(k)^2)/(1 + x^(prime(k)^2)) * Product_{k>=1} (1 + x^(prime(k)^2)).

A281545 Expansion of Sum_{k>=2} x^prime(k)/(1 + x^prime(k)) * Product_{k>=2} (1 + x^prime(k)).

Original entry on oeis.org

0, 0, 1, 0, 1, 0, 1, 2, 0, 2, 1, 2, 1, 2, 3, 4, 1, 4, 4, 4, 6, 4, 7, 6, 6, 8, 9, 8, 10, 6, 13, 12, 12, 14, 15, 16, 16, 18, 23, 22, 19, 24, 24, 30, 28, 30, 33, 34, 34, 40, 44, 46, 44, 46, 58, 56, 60, 64, 65, 68, 70, 80, 86, 88, 87, 94, 101, 112, 114, 116, 125, 130, 132, 148, 159, 162, 163, 168, 190, 196
Offset: 1

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Author

Ilya Gutkovskiy, Jan 23 2017

Keywords

Comments

Total number of parts in all partitions of n into distinct odd primes.

Examples

			a(23) = 7 because we have [23], [13, 7, 3], [11, 7, 5] and 1 + 3 + 3 = 7.
		

Crossrefs

Programs

  • Mathematica
    nmax = 80; Rest[CoefficientList[Series[Sum[x^Prime[k]/(1 + x^Prime[k]), {k, 2, nmax}] Product[1 + x^Prime[k], {k, 2, nmax}], {x, 0, nmax}], x]]
  • PARI
    sumparts(n, pred)={sum(k=1, n, 1 - 1/(1+pred(k)*x^k) + O(x*x^n))*prod(k=1, n, 1+pred(k)*x^k + O(x*x^n))}
    {my(n=60); Vec(sumparts(n, v->v>2 && isprime(v)), -n)} \\ Andrew Howroyd, Dec 28 2017

Formula

G.f.: Sum_{k>=2} x^prime(k)/(1 + x^prime(k)) * Product_{k>=2} (1 + x^prime(k)).

A281668 Expansion of Sum_{p prime, i>=1} x^(p^i)/(1 + x^(p^i)) * Product_{p prime, j>=1} (1 + x^(p^j)).

Original entry on oeis.org

0, 1, 1, 1, 3, 2, 5, 3, 8, 7, 10, 12, 13, 20, 18, 26, 25, 36, 34, 45, 47, 59, 62, 71, 82, 91, 105, 112, 132, 143, 163, 174, 201, 220, 244, 266, 298, 327, 362, 388, 437, 470, 521, 558, 621, 671, 733, 788, 864, 938, 1011, 1100, 1182, 1295, 1379, 1501, 1606, 1753, 1861, 2017, 2158, 2335, 2493, 2672, 2871, 3078
Offset: 1

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Author

Ilya Gutkovskiy, Jan 26 2017

Keywords

Comments

Total number of parts in all partitions of n into distinct prime power parts (1 excluded).

Examples

			a(10) = 7 because we have [8, 2], [7, 3], [5, 3, 2] and 2 + 2 + 3 = 7.
		

Crossrefs

Programs

  • Mathematica
    nmax = 66; Rest[CoefficientList[Series[Sum[Floor[1/PrimeNu[i]] x^i/(1 + x^i), {i, 2, nmax}] Product[1 + Floor[1/PrimeNu[j]] x^j, {j, 2, nmax}], {x, 0, nmax}], x]]

Formula

G.f.: Sum_{p prime, i>=1} x^(p^i)/(1 + x^(p^i)) * Product_{p prime, j>=1} (1 + x^(p^j)).

A186409 Total number of parts in all partitions of prime(n).

Original entry on oeis.org

3, 6, 20, 54, 275, 556, 1965, 3498, 10206, 43453, 68135, 242812, 536104, 785437, 1644136, 4712040, 12760906, 17591088, 44736332, 81493581, 109311863, 257863391, 448980978, 1007135164, 2840344772, 4695605081, 6015397025, 9803584533, 12473509636, 20063812526
Offset: 1

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Author

Omar E. Pol, Aug 11 2011

Keywords

Examples

			For n = 3 the third prime number is 5; the partitions of 5 are [5], [4, 1], [3, 2], [3, 1, 1], [2, 2, 1], [2, 1, 1, 1], [1, 1, 1, 1, 1]; there are 20 parts, so a(3) = 20.
		

Crossrefs

Formula

a(n) = A006128(A000040(n)) = A006128(prime(n)).

A279412 Expansion of Sum_{k>=1} prime(k)*x^prime(k)/(1 + x^prime(k)) * Product_{k>=1} (1 + x^prime(k)).

Original entry on oeis.org

0, 2, 3, 0, 10, 0, 14, 8, 9, 20, 11, 24, 26, 28, 30, 48, 34, 72, 57, 80, 84, 88, 115, 120, 125, 156, 135, 168, 203, 180, 279, 224, 297, 306, 315, 396, 407, 418, 507, 480, 574, 630, 645, 748, 720, 828, 893, 960, 1029, 1150, 1122, 1300, 1378, 1458, 1650, 1624, 1824, 1856, 2065, 2220, 2379, 2480, 2646, 2816, 2925
Offset: 1

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Author

Ilya Gutkovskiy, Apr 11 2017

Keywords

Comments

Sum of all parts of all partitions of n into distinct primes.

Examples

			a(12) = 24 because we have [7, 5], [7, 3, 2] and 2*12 = 24.
		

Crossrefs

Programs

  • Mathematica
    nmax = 65; Rest[CoefficientList[Series[Sum[Prime[k] x^Prime[k]/(1 + x^Prime[k]), {k, 1, nmax}] Product[1 + x^Prime[k], {k, 1, nmax}], {x, 0, nmax}], x]]
    nmax = 65; Rest[CoefficientList[Series[x D[Product[1 + x^Prime[k], {k, 1, nmax}], x], {x, 0, nmax}], x]]

Formula

G.f.: Sum_{k>=1} prime(k)*x^prime(k)/(1 + x^prime(k)) * Product_{k>=1} (1 + x^prime(k)).
G.f.: x*f'(x), where f(x) = Product_{k>=1} (1 + x^prime(k)).
a(n) = n*A000586(n).

A281667 Expansion of Sum_{i>=1} mu(i)^2*x^i/(1 + x^i) * Product_{j>=1} (1 + mu(j)^2*x^j), where mu() is the Moebius function (A008683).

Original entry on oeis.org

1, 1, 3, 2, 3, 6, 5, 9, 10, 12, 15, 16, 20, 24, 27, 38, 41, 48, 56, 62, 78, 88, 101, 120, 131, 149, 174, 189, 221, 243, 278, 318, 349, 394, 444, 491, 556, 622, 693, 773, 849, 953, 1048, 1158, 1292, 1422, 1568, 1735, 1901, 2101, 2307, 2534, 2795, 3060, 3357, 3681, 4024, 4404, 4809, 5245, 5734, 6242, 6805, 7418
Offset: 1

Views

Author

Ilya Gutkovskiy, Jan 26 2017

Keywords

Comments

Total number of parts in all partitions of n into distinct squarefree parts (A005117).

Examples

			a(8) = 9 because we have [7, 1], [6, 2], [5, 3], [5, 2, 1] and 2 + 2 + 2 + 3 = 9.
		

Crossrefs

Programs

  • Mathematica
    nmax = 64; Rest[CoefficientList[Series[Sum[MoebiusMu[i]^2 x^i/(1 + x^i), {i, 1, nmax}] Product[1 + MoebiusMu[j]^2 x^j, {j, 1, nmax}], {x, 0, nmax}], x]]

Formula

G.f.: Sum_{i>=1} mu(i)^2*x^i/(1 + x^i) * Product_{j>=1} (1 + mu(j)^2*x^j).
Showing 1-7 of 7 results.