1,2

For n>1, a(n) = n^2 iff n is prime.

a(4) = 15 = sum of row 4 terms of triangle A134674: (4, + 3 + 4 + 4).

Cf. A134674.

Sequence in context: A065893 A052116 A109641 this_sequence A050530 A102084 A030664

Adjacent sequences: A134672 A134673 A134674 this_sequence A134676 A134677 A134678

nonn

Gary W. Adamson (qntmpkt(AT)yahoo.com), Nov 05 2007