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 A325809 Let k = A228058(n). a(n) is the number of ways to partition the divisors of k into complementary subsets x and y so that the (k-Sum(x)) and (k-Sum(y)) are coprime. 3
 8, 12, 8, 16, 8, 15, 16, 8, 113, 16, 8, 15, 16, 7, 14, 8, 8, 13, 16, 15, 8, 15, 14, 8, 15, 254, 8, 16, 8, 128, 16, 16, 16, 15, 8, 15, 16, 15, 8, 16, 13, 15, 7, 13, 16, 8, 16, 43008, 8, 8, 126, 8, 15, 15, 15, 8, 16, 8, 14, 8, 15, 16, 8, 16, 60672, 15, 256, 13, 16, 7, 103, 16, 16, 8, 16, 16, 16, 8, 2015, 16, 8, 15, 16, 39093, 16 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The smallest value known so far occurs as a(449) = 6. A228058(449) = 23837 = 11^2 * 197. LINKS Antti Karttunen, Table of n, a(n) for n = 1..1158 FORMULA a(n) = A325807(A228058(n)). PROG (PARI) up_to = 25000; 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)); A228058list(up_to) = { my(v=vector(up_to), k=0, n=0); while(k0, s += (b%2)*v[i]; i++; b >>= 1); (s); }; A325809(n) = A325807(A228058(n)); CROSSREFS Cf. A228058, A325807, A325819. Sequence in context: A160862 A152077 A215696 * A173461 A335160 A295782 Adjacent sequences: A325806 A325807 A325808 * A325810 A325811 A325812 KEYWORD nonn AUTHOR Antti Karttunen, May 25 2019 STATUS approved

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Last modified April 14 07:58 EDT 2024. Contains 371655 sequences. (Running on oeis4.)