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A085887 Let r and s be such that r + s = n; a(n) = minimum value of tau(r) + tau(s). 2
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,1

COMMENTS

a(p+1) = 3 if p is a prime. a(n) = 4 if n is the sum of two primes. For all even numbers > 4, a(n) = 4 by Goldbach's conjecture.

LINKS

Antti Karttunen, Table of n, a(n) for n = 2..16385

EXAMPLE

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.

PROG

(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

CROSSREFS

Cf. A085883.

Sequence in context: A096344 A030349 A285203 * A305716 A297616 A213251

Adjacent sequences:  A085884 A085885 A085886 * A085888 A085889 A085890

KEYWORD

nonn

AUTHOR

Amarnath Murthy, Jul 08 2003

EXTENSIONS

More terms from David Wasserman, Feb 10 2005

STATUS

approved

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Last modified February 22 18:03 EST 2020. Contains 332148 sequences. (Running on oeis4.)