1,2

For a(n) = 2111, 1+2+3+4+5+7+8+,..,+2111 = 323761 = 569^2.

Cf. A000961, A025475.

Sequence in context: A015293 A159812 A146895 this_sequence A046334 A046382 A107528

Adjacent sequences: A068340 A068341 A068342 this_sequence A068344 A068345 A068346

nonn

Naohiro Nomoto (n_nomoto(AT)yabumi.com), Mar 08 2002