login

Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.

Total number of Y shapes in all tilings of a 5 X n rectangle with pentominoes of any shape.
2

%I #6 Feb 06 2017 18:58:00

%S 0,0,0,12,224,2096,17732,160624,1498176,13404068,115123856,980282312,

%T 8327179132,70264899456,587727020332,4882463109244,40378339971868,

%U 332612594766452,2729309532474820,22316919930250328,181922495487675520,1479018078159317720

%N Total number of Y shapes in all tilings of a 5 X n rectangle with pentominoes of any shape.

%H Alois P. Heinz, <a href="/A247745/b247745.txt">Table of n, a(n) for n = 0..500</a>

%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Pentomino">Pentomino</a>

%F a(n) = Sum_{k>0} k * A247712(n,k).

%Y Cf. A174249, A233427, A247712.

%K nonn

%O 0,4

%A _Alois P. Heinz_, Sep 23 2014