OFFSET
1,1
EXAMPLE
Contribution from Donovan Johnson, Jun 11 2012: (Start)
Let tri(n) = n*(n+1)/2. Then
a(1) = 3 = tri(2).
a(2) = 36 = tri(3)^2.
a(3) = 300 = tri(2) * tri(4)^2.
a(4) = 1485 = tri(2)^3 * tri(10).
a(5) = 3240 = tri(2)^2 * tri(3)^2 * tri(4).
a(6) = 265356 = tri(2)^4 * tri(8) * tri(13).
265356 = tri(2)^3 * tri(3) * tri(6) * tri(12).
a(7) = 265356 = tri(2)^4 * tri(3)^2 * tri(13).
a(8) = 21520080 = tri(2)^6 * tri(8) * tri(40).
a(9) = 21520080 = tri(2)^6 * tri(3)^2 * tri(40).
a(10) = 193720086 = tri(2)^7 * tri(3) * tri(6) * tri(37).
a(11) = 1743362676 = tri(2)^8 * tri(3)^2 * tri(121).
a(12) = 141214502520 = tri(2)^10 * tri(8) * tri(364).
141214502520 = tri(2)^8 * tri(3) * tri(5) * tri(13) * tri(72).
a(13) = 141214502520 = tri(2)^10 * tri(3)^2 * tri(364).
141214502520 = tri(2)^10 * tri(4) * tri(13) * tri(72).
a(14) = 11438393835996 = tri(2)^12 * tri(8) * tri(1093).
a(15) = 11438393835996 = tri(2)^12 * tri(3)^2 * tri(1093).
a(16) = 926510072902560 = tri(2)^14 * tri(8) * tri(3280).
a(17) = 926510072902560 = tri(2)^14 * tri(3)^2 * tri(3280).
a(18) = 75047317454789316 = tri(2)^16 * tri(8) * tri(9841).
a(19) = 75047317454789316 = tri(2)^16 * tri(3)^2 * tri(9841).
a(20) = 6078832727785072200 = tri(2)^18 * tri(8) * tri(29524).
a(21) = 6078832727785072200 = tri(2)^18 * tri(3)^2 * tri(29524). (End)
CROSSREFS
KEYWORD
nonn
AUTHOR
T. D. Noe, Jun 11 2012
EXTENSIONS
Terms a(3) to a(21) by Donovan Johnson, Jun 11 2012
STATUS
approved