A072690 a(n) = (n - A048760(n)) * (A048761(n) - n).

0, 2, 2, 0, 4, 6, 6, 4, 0, 6, 10, 12, 12, 10, 6, 0, 8, 14, 18, 20, 20, 18, 14, 8, 0, 10, 18, 24, 28, 30, 30, 28, 24, 18, 10, 0, 12, 22, 30, 36, 40, 42, 42, 40, 36, 30, 22, 12, 0, 14, 26, 36, 44, 50, 54, 56, 56, 54, 50, 44, 36, 26, 14, 0, 16, 30, 42, 52, 60, 66, 70, 72, 72, 70, 66

Offset

1,2

Comments

a(n)=0 iff n is a square.

Links

Table of n, a(n) for n=1..75.

Formula

a(n) = A053186(n) * (A072689(n) - A053186(n)).

Crossrefs

a(n) = A053186(n) * A068527(n).

Sequence in context: A168587 A320119 A100240 * A199454 A244130 A180813

Adjacent sequences: A072687 A072688 A072689 * A072691 A072692 A072693

Keyword

nonn

Author

Reinhard Zumkeller, Jul 02 2002

Status

approved