A097497 Floor( prime(n)*(prime(n)+prime(n+1))/prime(n+1)).

3, 4, 8, 11, 20, 22, 32, 34, 41, 56, 56, 70, 80, 82, 88, 100, 116, 116, 130, 140, 140, 154, 160, 170, 190, 200, 202, 212, 214, 213, 250, 256, 272, 268, 296, 296, 308, 322, 328, 340, 356, 352, 380, 382, 392, 386, 410, 442, 452, 454, 460, 476, 472, 496, 508, 520

Offset

1,1

Comments

if seq(n+1) - seq(n) = 0 or 2 then prime(n) and prime(n+1) are often twins.

Links

Table of n, a(n) for n=1..56.

Formula

Prime(n) is to prime(n+1) as x is to prime(n)+prime(n+1)

Example

Starting with the second prime: 3 is to 5 as x is to 8. x = 8*3/5 => 4

Prog

(PARI) p(n) = for(x=1, n, y=prime(x+1)*prime(x+2)/prime(x)+.0; print1(floor(y)", "))

Crossrefs

Sequence in context: A212550 A024786 A299069 * A332681 A279328 A006167

Adjacent sequences: A097494 A097495 A097496 * A097498 A097499 A097500

Keyword

frac,nonn

Author

Cino Hilliard, Aug 24 2004

Status

approved