[seqfan] computability of A080075 Proth numbers
Georgi Guninski
guninski at guninski.com
Mon Aug 16 12:50:51 CEST 2010
A080075 Proth numbers: of the form k*2^m + 1 for k odd, m >= 1 and 2^m >
k
machine analysis seems to suggest these relations (verified to 10 000
against the OEIS bfile)
a(2*n-1) = (4*a(n - 1) - 3)
a(2*n) = ( 2*a(n - 1) + 2*a(n) - 3 )
a(2*n+1) = (4*a(n) - 3)
a(n+1) = (-a(n - 1) + 2*a(n))
OR (these are the roots of a quadratic relation, a possible approach may
be to take the smaller proth of them)
a(n+1) = (-2*a(n - 1) + 3*a(n))
doubling formulas resemble "divide and conquer sequences" - do proth
numbers have generating function ?
--
joro
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