A225068 Least octagonal (8-gonal) number that is the product of n octagonal numbers greater than 1. 8, 1408, 2165800, 37333296, 19384601600, 69370076160, 69370076160, 56288711711232000, 7917914554368000000, 199449790781142859776 1 8 2 1408 3 2165800 4 37333296 5 19384601600 6 69370076160 7 69370076160 8 56288711711232000 9 7917914554368000000 10 199449790781142859776 a(1) = 8 = oct(2) = oct(2) Indices: 2 Values: 8 a(2) = 1408 = oct(22) = oct(2) * oct(8) Indices: 2,8 Values: 8,176 a(3) = 2165800 = oct(850) = oct(4) * oct(5) * oct(17) Indices: 4,5,17 Values: 40,65,833 a(4) = 37333296 = oct(3528) = oct(3)^2 * oct(8) * oct(13) Indices: 3,3,8,13 Values: 21,21,176,481 a(5) = 19384601600 = oct(80384) = oct(2)^2 * oct(5) * oct(14) * oct(53) Indices: 2,2,5,14,53 Values: 8,8,65,560,8321 a(6) = 69370076160 = oct(152064) = oct(3)^3 * oct(4) * oct(7) * oct(22) Indices: 3,3,3,4,7,22 Values: 21,21,21,40,133,1408 a(7) = 69370076160 = oct(152064) = oct(2) * oct(3)^3 * oct(4) * oct(7) * oct(8) Indices: 2,3,3,3,4,7,8 Values: 8,21,21,21,40,133,176 a(8) = 56288711711232000 = oct(136977750) = oct(2)^4 * oct(3) * oct(13) * oct(75) * oct(165) Indices: 2,2,2,2,3,13,75,165 Values: 8,8,8,8,21,481,16725,81345 a(9) = 7917914554368000000 = oct(1624593750) = oct(2)^2 * oct(4)^3 * oct(5) * oct(14) * oct(15) * oct(166) Indices: 2,2,4,4,4,5,14,15,166 Values: 8,8,40,40,40,65,560,645,82336 a(10) = 199449790781142859776 = oct(8153726976) = oct(2)^4 * oct(3) * oct(6)^2 * oct(13) * oct(61) * oct(126) Indices: 2,2,2,2,3,6,6,13,61,126 Values: 8,8,8,8,21,96,96,481,11041,47376