login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A084993 Total number of parts in all partitions of n into prime parts. 13
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Alois P. Heinz, Table of n, a(n) for n = 1..1000

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

EXAMPLE

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.

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 *)

CROSSREFS

Cf. A000607, A024938.

Sequence in context: A026317 A008768 A067593 * A046966 A225973 A035948

Adjacent sequences:  A084990 A084991 A084992 * A084994 A084995 A084996

KEYWORD

nonn

AUTHOR

Vladeta Jovovic, Jul 17 2003

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified June 24 08:22 EDT 2017. Contains 288697 sequences.