0,3

Table of n, a(n) for n=0..47.

153 is a triangular number and the product of digits 15 is also a triangular number.

(MAGMA) [t: n in [0..110] | IsSquare(8*p+1) where p is &*Intseq(t) where t is (n*(n+1) div 2)]; // Bruno Berselli, Jun 30 2011

Sequence in context: A343811 A071299 A338767 * A308849 A125567 A254957

Adjacent sequences: A061377 A061378 A061379 * A061381 A061382 A061383

nonn,base,easy

Amarnath Murthy, May 02 2001

More terms from Erich Friedman, May 08 2001

approved