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.

A064573 Number of partitions of n into parts which are all powers of the same prime.

This page as a plain text file.
%I A064573 #11 Oct 12 2018 00:51:54
%S A064573 0,1,2,4,5,8,9,13,15,20,21,29,30,37,40,50,51,64,65,80,84,99,100,123,
%T A064573 125,146,151,178,179,212,213,249,255,292,295,348,349,396,404,466,467,
%U A064573 535,536,611,622,697,698,801,803,900,910,1025,1026,1152,1156,1298,1311
%N A064573 Number of partitions of n into parts which are all powers of the same prime.
%C A064573 The exponents cannot all be zero.
%H A064573 Andrew Howroyd, <a href="/A064573/b064573.txt">Table of n, a(n) for n = 1..1000</a>
%F A064573 G.f.: Sum_{k>=1} 1/(Product_{r>=0} 1-x^(prime(k)^r)) - 1/(1-x). - _Andrew Howroyd_, Dec 29 2017
%e A064573 a(5)=5: 5^1, 3^1+2*3^0, 2^2+1, 2*2^1+1, 2^1+3*2^0
%e A064573 From _Gus Wiseman_, Oct 10 2018: (Start)
%e A064573 The a(2) = 1 through a(9) = 15 integer partitions:
%e A064573   (2)  (3)   (4)    (5)     (33)     (7)       (8)        (9)
%e A064573        (21)  (22)   (41)    (42)     (331)     (44)       (81)
%e A064573              (31)   (221)   (51)     (421)     (71)       (333)
%e A064573              (211)  (311)   (222)    (511)     (422)      (441)
%e A064573                     (2111)  (411)    (2221)    (2222)     (711)
%e A064573                             (2211)   (4111)    (3311)     (4221)
%e A064573                             (3111)   (22111)   (4211)     (22221)
%e A064573                             (21111)  (31111)   (5111)     (33111)
%e A064573                                      (211111)  (22211)    (42111)
%e A064573                                                (41111)    (51111)
%e A064573                                                (221111)   (222111)
%e A064573                                                (311111)   (411111)
%e A064573                                                (2111111)  (2211111)
%e A064573                                                           (3111111)
%e A064573                                                           (21111111)
%e A064573 (End)
%t A064573 Table[Length[Select[IntegerPartitions[n],PrimePowerQ[Times@@#]&]],{n,30}] (* _Gus Wiseman_, Oct 10 2018 *)
%o A064573 (PARI) first(n)={Vec(sum(k=2, n, if(isprime(k), 1/prod(r=0, logint(n,k), 1-x^(k^r) + O(x*x^n)) - 1/(1-x), 0)), -n)} \\ _Andrew Howroyd_, Dec 29 2017
%Y A064573 Cf. A028422, A064572, A064574, A064575, A064576, A064577, A319071, A320322, A320325.
%K A064573 easy,nonn
%O A064573 1,3
%A A064573 _Marc LeBrun_, Sep 20 2001
%E A064573 Name clarified by _Andrew Howroyd_, Dec 29 2017