The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A318587 Heinz numbers of integer partitions whose sum of reciprocals squared is 1. 5

%I

%S 2,81,8775,64827,950625,1953125,7022925,9055935,21781575,36020025,

%T 50124555,51883209,57909033,102984375,118978125,760816875,816747435,

%U 981059625,1206902781,1265058675,1387132263,2359670625,3902169375,4868424351,5222768733,5430160125

%N Heinz numbers of integer partitions whose sum of reciprocals squared is 1.

%C The Heinz number of an integer partition (y_1, ..., y_k) is prime(y_1) * ... * prime(y_k).

%e The sequence of integer partitions with Heinz numbers in this sequence begins: (1), (2222), (633222), (4444222), (66333322).

%t Select[Range[100000],Total[If[#==1,{},Cases[FactorInteger[#],{p_,k_}:>k/PrimePi[p]^2]]]==1&]

%Y Cf. A001222, A051908, A056239, A112798, A289506, A289507, A316855, A316856, A316857.

%Y Cf. A318584, A318585, A318586, A318588, A318589.

%K nonn

%O 1,1

%A _Gus Wiseman_, Aug 29 2018

%E a(6)-a(26) from _Alois P. Heinz_, Aug 30 2018

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

Last modified February 22 12:33 EST 2020. Contains 332136 sequences. (Running on oeis4.)