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A117221 Number of partitions of 3-smooth numbers. 6

%I #15 Oct 13 2021 08:27:42

%S 1,2,3,5,11,22,30,77,231,385,1575,3010,8349,17977,147273,386155,

%T 1741630,5392783,18004327,118114304,483502844,4351078600,22540654445,

%U 129913904637,1987276856363,15285151248481,133978259344888,365749566870782,3925922161489422,49005643635237875

%N Number of partitions of 3-smooth numbers.

%H Andrew Howroyd, <a href="/A117221/b117221.txt">Table of n, a(n) for n = 1..100</a>

%F a(n) = A000041(A003586(n)).

%t PartitionsP /@ Select[Range[1000], AllTrue[FactorInteger[#][[All, 1]], # <= 3 &] &] (* _Jean-François Alcover_, Oct 13 2021 *)

%o (PARI) \\ here is(n) is test for A003586 inclusion.

%o is(n)={forprime(p=2, 3, n/=p^valuation(n,p)); n==1}

%o seq(n)={my(A=List(), i=0); while(#A<n, i++; if(is(i), listput(A, numbpart(i)))); Vec(A)} \\ _Andrew Howroyd_, Jan 02 2020

%Y Cf. A000041, A003586, A090184, A117220, A117222.

%K nonn

%O 1,2

%A _Reinhard Zumkeller_, Mar 04 2006

%E More terms from _Michel Marcus_, Apr 20 2019

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Last modified April 24 22:17 EDT 2024. Contains 371964 sequences. (Running on oeis4.)