cp's OEIS Frontend

A001415 Number of ways of folding a 2 X n strip of stamps.

%I A001415 M1891 N0745 #54 Mar 22 2025 11:17:18
%S A001415 1,2,8,60,320,1980,10512,60788,320896,1787904,9381840,51081844,
%T A001415 266680992,1429703548,7432424160,39409195740,204150606976,
%U A001415 1073644675448,5545305620064,28980175671212,149302889205120
%N A001415 Number of ways of folding a 2 X n strip of stamps.
%C A001415 a(n), called G(n,2), is known to be divisible by 4n for n >= 2. - _Fred Lunnon_, Dec 08 2013
%D A001415 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
%D A001415 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H A001415 Robert Dickau, <a href="http://robertdickau.com/mapfolding.html">Map Folding</a>
%H A001415 Robert Dickau, <a href="http://demonstrations.wolfram.com/FoldingA2NSheetOfLabeledStamps/">Folding a 2xn Sheet of Labeled Stamps</a>, Wolfram Demonstrations Project
%H A001415 Hunter Hogan, <a href="https://github.com/hunterhogan/mapFolding">mapFolding: A computational framework for enumerating distinct folding patterns of rectangular maps</a>, GitHub repository, (2025).
%H A001415 W. F. Lunnon, <a href="http://dx.doi.org/10.1093/comjnl/14.1.75">Multi-dimensional map-folding</a>, Computer Journal 14 1971 75-80.
%H A001415 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/MapFolding.html">Map Folding</a>
%H A001415 <a href="/index/Fo#fold">Index entries for sequences obtained by enumerating foldings</a>
%K A001415 nonn,more
%O A001415 0,2
%A A001415 _N. J. A. Sloane_
%E A001415 a(12)-a(18) from _Fred Lunnon_, Dec 08 2013
%E A001415 a(19)-a(20) from _Hunter Hogan_, Mar 21 2025