A140109 Quartets of prime x, composites y, z and S for Heron's formula.

7, 15, 20, 42, 7, 24, 25, 84, 13, 14, 15, 84, 13, 84, 85, 546, 17, 8, 15, 60, 17, 9, 10, 36, 29, 20, 21, 210, 37, 12, 35, 210, 41, 9, 40, 180, 53, 45, 48, 1080, 73, 48, 55, 1320, 89, 39, 80, 1560, 97, 65, 72, 2340, 101, 20, 99, 990, 109, 60, 91, 2730, 113, 15, 112, 840

Offset

1,1

Comments

Heron's formula (x+y+z)*(x+y-z)*(x+z-y)*(y+z-x)/16=S^2

Links

Table of n, a(n) for n=1..64.

Example

The quartets are: (7, 15, 20, 42), (7, 24, 25, 84), (13, 14, 15, 84), etc.

Crossrefs

Cf. A140385, A140391, A140384.

Sequence in context: A297853 A298050 A115783 * A064397 A214467 A151971

Adjacent sequences: A140106 A140107 A140108 * A140110 A140111 A140112

Keyword

nonn

Author

Juri-Stepan Gerasimov, Jul 10 2008

Extensions

This should be replaced by four linked sequences! As it stands it is not a proper sequence. - N. J. A. Sloane, Jul 11 2008

Status

approved