A085887 Let r and s be such that r + s = n; a(n) = minimum value of tau(r) + tau(s).
2, 3, 3, 4, 3, 4, 3, 4, 4, 5, 3, 4, 3, 4, 4, 5, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 6, 3, 4, 3, 4, 4, 5, 4, 6, 3, 4, 4, 5, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 6, 3, 4, 4, 5, 4, 5, 3, 4, 3, 4, 4, 5, 4, 6, 3, 4, 4, 5, 3, 4, 3, 4, 4, 5, 4, 6, 3, 4, 4, 5, 3, 4, 4, 5, 4, 6, 3, 4, 4, 5, 4, 5, 4, 6, 3, 4, 4, 5, 3, 4, 3, 4, 4
Offset: 2
Keywords
Examples
a(8) = 3, the partitions are (1,7), (2,6), (3,5), (4,4) which give 3, 6, 4 and 6 as the sum of the number of divisors of both parts.
Links
- Antti Karttunen, Table of n, a(n) for n = 2..16385
Crossrefs
Cf. A085883.
Programs
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Mathematica
Table[Min[Total/@DivisorSigma[0,IntegerPartitions[n,{2}]]],{n,2,120}] (* Harvey P. Dale, Mar 18 2023 *)
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PARI
A085887(n) = { my(m=0,k); for(r=1,n-1,if((m > k=(numdiv(r)+numdiv(n-r)))||!m, m = k)); m; }; \\ Antti Karttunen, Dec 14 2017
Extensions
More terms from David Wasserman, Feb 10 2005
Comments