1,2

This sequence is to A003215 as A002828 is to A000290, and as A061336 is to A000217.

Lars Blomberg, Table of n, a(n) for n = 1..10000

a(21) = 3, because 21 = 19 + 1 + 1 = 7 + 7 + 7, so there are two ways to express 21 as the sum of 3 hex numbers, but no way to express 21 as the sum of 2 hex numbers.

Sequence in context: A190596 A053842 A010885 * A053828 A033927 A104414

Adjacent sequences: A234530 A234531 A234532 * A234534 A234535 A234536

nonn

Allan C. Wechsler, Dec 27 2013

a(27)-a(87) from Lars Blomberg, Jan 07 2014

approved