The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A244344 Numbers such that the largest prime factor equals the sum of the 4th power of the other prime factors. 1

%I #16 Jan 22 2022 00:08:12

%S 582,1164,1746,2328,3492,4656,5238,6410,6984,9312,10476,12820,13968,

%T 15714,18624,20952,25640,27936,31428,32050,33838,37248,41904,47142,

%U 51280,55872,56454,62856,64100,67676,74496,83808,94284,102560,111744,112908,125712,128200

%N Numbers such that the largest prime factor equals the sum of the 4th power of the other prime factors.

%C Observation: it seems that the prime divisors of a majority of numbers n are of the form {2, p, q} with q = 2^4 + p^4, but there exists more rarely odd numbers with more prime divisors (example from Michel Marcus: 3955413 = 3*7*11*17123).

%H Amiram Eldar, <a href="/A244344/b244344.txt">Table of n, a(n) for n = 1..1500</a>

%e 582 is in the sequence because the prime divisors of 582 are 2, 3 and 97 => 2^4 + 3^4 = 97.

%t fpdQ[n_]:=Module[{f=Transpose[FactorInteger[n]][[1]]},Max[f]-Total[Most[f]^4]==0];Union[Select[Range[2,5*10^5],fpdQ]]

%Y Cf. A094479, A193411, A185077.

%K nonn

%O 1,1

%A _Michel Lagneau_, Jun 26 2014

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

Last modified August 5 17:42 EDT 2024. Contains 374953 sequences. (Running on oeis4.)