OFFSET
1,1
EXAMPLE
a(1)=15 because 3*5=15: 15+1=4^2 and 15-1=2*7;
a(2)=35 because 5*7=35: 35+1=6^2 and 35-1=2*17;
a(3)=143 because 11*13=143: 143+1=12^2 and 143-1=2*71;
a(4)=899 because 29*31=899: 899+1=30^2 and 899-1=2*449;
CROSSREFS
KEYWORD
nonn
AUTHOR
Giovanni Teofilatto, May 26 2005
EXTENSIONS
Terms beyond a(6) from R. J. Mathar, Jun 28 2010
STATUS
approved