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A354697
a(n) is the least integer that can be written in two or more ways as the product of the integers in two subsets of its A070824(a(n)) nontrivial divisors, each of size n and with empty intersection.
3
12, 120, 720, 10080, 110880, 1814400, 26611200, 518918400, 10378368000, 261534873600, 5928123801600, 168951528345600, 4505374089216000, 152056375511040000, 4663062182338560000, 167870238564188160000, 6463004184721244160000, 249902828475888107520000, 10495918795987300515840000
OFFSET
2,1
COMMENTS
a(6) <= 110880 = 2*3*6*10*14*22 = 4*5*7*8*9*11.
LINKS
FORMULA
A070824(a(n)) >= 2*n.
EXAMPLE
a(2) = 12 = 2*6 = 3*4,
a(3) = 120 = 2*3*20 = 4*5*6,
a(4) = 720 = 2*4*9*10 = 3*5*6*8,
a(5) = 10080 = 2*3*6*10*28 = 4*5*7*8*9.
a(6) = 110880 = 2*3*6*10*14*22 = 4*5*7*8*9*11.
a(7) = 1814400 = 2*3*4*14*15*18*20 = 5*6*7*8*9*10*12.
CROSSREFS
KEYWORD
nonn,hard
AUTHOR
Hugo Pfoertner, Jun 03 2022
EXTENSIONS
a(6) confirmed by and a(7)-a(13) from David A. Corneth, Jun 04 2022
a(14) onwards from Zhao Hui Du, May 12 2024
STATUS
approved