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A127181 a(1)=a(2)=1. a(n) = smallest possible (product of b(k)'s + product of c(k)'s), where the sequence's terms a(1) through a(n-1) are partitioned somehow into {b(k)} and {c(k)}. 1
1, 1, 2, 3, 5, 11, 37, 221, 3361, 190777, 83199527, 760382931109, 662056785094857629, 538451433632092674800570837, 12495147956629620251492228703104952798089 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Every term of the sequence is coprime to every other term.

LINKS

Table of n, a(n) for n=1..15.

EXAMPLE

By partitioning (a(1),a(2),...a(7)) = (1,1,2,3,5,11,37) into {b(k)} and {c(k)} so that {b(k)} = (1,2,5,11) and {c(k)} = (1,3,37), then (product of b(k)'s + product of c(k)'s) is minimized. Therefore a(8) = 1*2*5*11 + 1*3*37 = 221.

MATHEMATICA

Nest[ Module[ {prod=Times@@#1}, Append[ #, Min[ #+prod/#&/@Times@@@Union[ Subsets[ # ] ] ] ] ]&, {1, 1, 2, 3}, 11 ] (Peter Pein (petsie(AT)dordos.net), Jan 07 2007)

CROSSREFS

Cf. A127180.

Sequence in context: A006721 A111289 A255420 * A323611 A113734 A222007

Adjacent sequences:  A127178 A127179 A127180 * A127182 A127183 A127184

KEYWORD

nonn

AUTHOR

Leroy Quet, Jan 07 2007

EXTENSIONS

More terms from Peter Pein (petsie(AT)dordos.net), Jan 07 2007

STATUS

approved

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Last modified September 20 22:20 EDT 2019. Contains 327252 sequences. (Running on oeis4.)