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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.

A225981 Number of nX7 binary arrays whose sum with another nX7 binary array containing no more than two 1s has rows and columns in lexicographically nondecreasing order.

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%I A225981 #5 Jul 23 2025 05:26:11
%S A225981 64,1616,49811,1825607,69784592,2513743785,80901937149,2279339811483,
%T A225981 56056577764123,1210023577040820,23129995837890549,395389054254892996,
%U A225981 6101927873439814335,85761387564101647001
%N A225981 Number of nX7 binary arrays whose sum with another nX7 binary array containing no more than two 1s has rows and columns in lexicographically nondecreasing order.
%C A225981 Column 7 of A225982
%e A225981 Some solutions for n=3
%e A225981 ..0..0..1..1..0..1..1....0..0..0..1..1..1..1....0..0..1..1..1..1..1
%e A225981 ..1..0..0..0..1..1..1....0..1..0..0..0..0..0....0..0..1..1..1..0..1
%e A225981 ..1..1..0..0..1..1..1....1..1..0..0..0..1..0....1..1..0..1..1..0..1
%K A225981 nonn
%O A225981 1,1
%A A225981 _R. H. Hardin_ May 22 2013

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