A243200 Let A242720(n)-3 = prime(l)*prime(m), l<=m; a(n)=m-l.

0, 1, 1, 3, 1, 1, 1, 3, 4, 4, 3, 2, 2, 6, 6, 5, 1, 1, 5, 2, 2, 2, 10, 5, 5, 3, 3, 3, 2, 2, 2, 1, 1, 1, 3, 2, 2, 5, 1, 1, 3, 3, 3, 3, 6, 7, 4, 1, 1, 1, 1, 1, 4, 4, 1, 1, 1, 1, 3, 3, 3, 1, 1, 1, 2, 2, 2, 2, 2, 2, 8, 6, 6, 6, 1, 1, 1, 1, 1, 1, 7, 1, 1, 1, 4, 2, 2

Offset: 2

Author

Vladimir Shevelev, Jun 01 2014

Keywords

• nonn

Comments

Since for a prime p>3, p^2 == 1 (mod 3), then for n>2, A242720(n) is not equal to p^2 + 3 (otherwise, lpf(A242720(n) - 1) = 3). So, the sequence has only zero term a(2).

Crossrefs

Cf. A242720, A242719, A243154, A243158.

Extensions

More terms from Peter J. C. Moses, Jun 01 2014