[seqfan] Announcement: 2015 John Riordan Prize awarded to Max. A. Alekseyev

[Neil Sloane]

Dear Sequence Fans:

The 2015 John Riordan Prize Committee reached its decision today -- the
prize will be awarded to Max. A. Alekseyev of George Washington University.

The following announcement has been added to the OEIS Wiki page
describing the Riordan Prize: https://oeis.org/wiki/RiordanPrize.

Neil Sloane, President, The OEIS Foundation, Inc.

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Announcement: 2015 John Riordan Prize awarded to Max. A. Alekseyev

January 20 2016. Max. A. Alekseyev of George Washington University will
receive the 2015 John Riordan Prize from the OEIS Foundation for the
results in his paper "On Enumeration of Paths in Catalan-Schroeder
Lattices" (to appear on the arXiv). The John Riordan Prize comes with a
$1000 prize from the OEIS Foundation.

The classical Catalan and Large Schroeder numbers respectively count
below-diagonal paths from (0,0) to (n,n) in two classes of directed graphs.
In his paper, Alekseyev counts paths in a graph which looks like the
Catalan graph below the diagonal and the Schroeder graph above the
diagonal. From this he is able to find generating functions for 22
sequences (A026769-A026779, A026780-A026790) which had been in the On-Line
Encyclopedia of Integer Sequences (the OEIS, https://oeis.org) for sixteen
years without any formula being discovered.

The 2015 John Riordan Prize was offered for the best solution in 2015 to an
open problem in the OEIS. Twenty-three nominations were received, and the
decision was not an easy one. The deciding factor in awarding the prize to
Max. Alekseyev was the unexpected nature of his result (this was much more
than finding a proof for an already-conjectured formula), the number of
sequences to which it could be applied, and the number of years they had
been in the OEIS.