--- In

primenumbers@yahoogroups.com, "Mike Oakes"

<mikeoakes2@...> wrote [with unfailing courtesy]:

> lucasU(338,25,11584)-5*lucasU(338,25,11583)

> I guess Chris would expect the last of these as being the most

> "canonical"? And I concur, it being also the shortest.

Yes, Mike, that last form is by far the neatest,

if one removes the unnecessary "lucas", which should

be well understood, when one speaks of "U" or "V".

1) François Édouard Anatole Lucas defined the integer sequence

U(P,Q,n) = P*U(P,Q,n-1) - Q*U(P,Q,n-2),

with U(P,Q,0) = 0 and U(P,Q,1) = 1,

in terms of elementary arithmetic.

2) I like to imagine that Derrick Norman Lehmer (1867-1938) saw that

U(P,Q^2,2*k+1) = U(P,Q^2,k+1)^2 - (Q*U(P,Q^2,n))^2

and told his son: "Go look at the factors for your Ph.D."

3) Certainly, Derrick Henry Lehmer (1905-1991) did study

U(P,Q^2,k+1) - Q*U(P,Q^2,k)

being very well aware of the super-Lucasian extension to powers

of algebraic numbers of degree 4, in the wider complex plane.

4) Mike Oakes has found that the Lehmer number

U(P,Q^2,k+1) - Q*U(P,Q^2,k)

is probably prime, when P = 338, Q = 5, k = 11583.

5) David Broadhurst is able to characterize this

circumstance without using a dirty 4-letter word :-)

Thank ye, kindly, Sir, for this interesting thread!

David, pp SSSR