A372794
Number of pairs of two disjoint sets of n positive integers with product A354457(n).
Original entry on oeis.org
1, 1, 3, 4, 31, 15, 55, 110, 280, 797, 1419, 3557, 5647, 19559, 59708, 360726, 346487, 2018032, 2106172, 13228494, 13994982, 65426469, 110980446, 257148638, 660593345, 1966842579, 3909078573, 20820932559, 26864715089, 144689720443, 307476230099, 571509614773
Offset: 2
For n=2, there exists only one pair of sets <{1,6},{2,3}> with product 1*6=2*3, so a(2)=1.
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.
Original entry on oeis.org
12, 120, 720, 10080, 110880, 1814400, 26611200, 518918400, 10378368000, 261534873600, 5928123801600, 168951528345600, 4505374089216000, 152056375511040000, 4663062182338560000, 167870238564188160000, 6463004184721244160000, 249902828475888107520000, 10495918795987300515840000
Offset: 2
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.
Showing 1-2 of 2 results.
Comments