cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A123809 Number of ways to build a contiguous building with n LEGO blocks of size 1 X 7 on top of a fixed block of the same size so that the building is flat, i.e., with all blocks in parallel position and symmetric after a rotation by 180 degrees.

Table of values

n a(n)
1 1
2 4
3 7
4 34
5 85
6 461
7 1175
8 6871
9 18807
10 112406
11 318571
12 1936113
13 5653062
14 34848639
15 103771770
16 645701202
17 1955873614

List of values

[1, 4, 7, 34, 85, 461, 1175, 6871, 18807, 112406, 318571, 1936113, 5653062, 34848639, 103771770, 645701202, 1955873614]

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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