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!)
 A325320 Sum of proper divisors of A228058(n) that are not squarefree; a(n) = -A325314(A228058(n)). 12
 9, 9, 9, 49, 9, 25, 9, 9, 297, 25, 9, 9, 121, 49, 9, 25, 9, 49, 169, 9, 9, 25, 9, 9, 25, 585, 9, 25, 9, 729, 9, 49, 289, 25, 9, 121, 9, 9, 9, 361, 49, 25, 49, 121, 9, 9, 9, 2049, 25, 9, 1161, 9, 25, 9, 25, 9, 49, 9, 529, 25, 9, 25, 9, 169, 2381, 49, 1449, 9, 9, 9, 1593, 9, 25, 9, 121, 9, 49, 9, 2889, 9, 25, 289, 9, 2997, 9 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS All terms are of the form 4k+1, A016813. If a(n) is never equal to A325319(n), then there are no odd perfect numbers. LINKS Antti Karttunen, Table of n, a(n) for n = 1..25000 FORMULA a(n) = -A325314(A228058(n)) = A162296(A228058(n)) - A228058(n). a(n) = A325319(n) - A325379(n) = A325378(n) - A325319(n). a(n) < A001065(A228058(n)) for all n. PROG (PARI) A162296(n) = sumdiv(n, d, d*(1-issquarefree(d))); A325314(n) = (n - A162296(n)); isA228058(n) = if(!(n%2)||(omega(n)<2), 0, my(f=factor(n), y=0); for(i=1, #f~, if(1==(f[i, 2]%4), if((1==y)||(1!=(f[i, 1]%4)), return(0), y=1), if(f[i, 2]%2, return(0)))); (y)); k=0; n=0; while(k<100, n++; if(isA228058(n), k++; print1(-A325314(n), ", "))); CROSSREFS Cf. A016813, A162296, A228058, A325313, A325319, A325378, A325379. Sequence in context: A160761 A082049 A282242 * A282910 A282599 A282957 Adjacent sequences:  A325317 A325318 A325319 * A325321 A325322 A325323 KEYWORD nonn AUTHOR Antti Karttunen, Apr 22 2019 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
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified May 14 22:40 EDT 2021. Contains 343909 sequences. (Running on oeis4.)