1,1

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;

Sequence in context: A142591 A074480 A037074 this_sequence A027442 A074891 A134509

Adjacent sequences: A107420 A107421 A107422 this_sequence A107424 A107425 A107426

nonn

Giovanni Teofilatto (g.teofilatto(AT)tiscalinet.it), May 26 2005