3,1

The sequence is not monotonically increasing as a(27) = 55369 > 54146 = a(28).

Table of n, a(n) for n=3..41.

a(3)=16 since 16=1+15=6+10, such that 1,15,6,10 are all triangular numbers (A000217) and there are no other positive numbers less than 16 with such a property.

Sequence in context: A235566 A186842 A231840 * A121863 A121864 A221485

Adjacent sequences: A199806 A199807 A199808 * A199810 A199811 A199812

nonn

Vladimir Shevelev, Dec 16 2013

More terms from Peter J. C. Moses, Dec 16 2013

approved