OFFSET
1,2
COMMENTS
a(15) > 10^28. - Donovan Johnson, Jun 28 2011
FORMULA
Solutions to the Diophantine equation b^2*c^3 = d(3d-1)/2. [Charles R Greathouse IV,Jun 28 2011]
EXAMPLE
94109401=7921*(3*7921-1)/2 is the 7921st pentagonal number and 94109401=89^2*109^2.
CROSSREFS
KEYWORD
nonn
AUTHOR
Giovanni Resta,Jan 31 2006
EXTENSIONS
a(8) fromDonovan Johnson,Dec 07 2008
a(9) fromDonovan Johnson,Jun 20 2011
a(10)-a(14) fromDonovan Johnson,Jun 28 2011
STATUS
approved