help needed with a duplicate

Hans Havermann pxp at rogers.com
Sun Jun 24 02:30:57 CEST 2007


sixth term can be 11 as well as 10. The twelfth term can be 11 or 19  
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Date: Sat, 23 Jun 2007 19:38:41 -0700
From: "Jonathan Post" <jvospost3 at gmail.com>
To: "Sequence Fans" <seqfan at ext.jussieu.fr>,
   "jonathan post" <jvospost2 at yahoo.com>
Subject: Smallest Fibonacci number with Hamming weight n
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Smallest Fibonacci number with Hamming weight n (i.e. smallest
semiprime with exactly n ones when written in binary).

0, 1, 3, 13, 89, 55, 377, 1597, 987, 121393, 39088169, 28657, 514229,
3524578, 24157817, ...

a(n) = MIN{A000045(k): A000129(A000045(k)) = n}.

This does not seem to be in OEIS, to my surprise, and is legitimate as
smallest square, prime, semiprime, triangular number of Hamming weight
n which are in OEIS already.

Does anyone want to extend, edit, provide Mathematica or MAGMA or
Maple code, or suggest a comment? This looks ideal for an elementary
programming course: two standard functions together at last...

Thank you,

Jonathan Vos Post





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