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.

Showing 1-9 of 9 results.

A180752 Half the number of nX3 binary arrays with each element equal to at least two neighbors.

Original entry on oeis.org

0, 1, 1, 2, 3, 7, 14, 31, 67, 148, 325, 717, 1580, 3485, 7685, 16950, 37383, 82451, 181850, 401083, 884615, 1951080, 4303241, 9491097, 20933272, 46169785, 101830665, 224594602, 495358987, 1092548639, 2409691878, 5314742743
Offset: 1

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Author

R. H. Hardin Sep 20 2010

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Comments

Column 3 of A180760

Formula

Empirical: a(n) = 2*a(n-1) + a(n-2) - a(n-3) - a(n-5).
Empirical: G.f.: -x^2*(-1+x+x^3+x^2) / ( (x-1)*(1+x)*(x^3+2*x-1) ). a(n)-a(n-2) = A052980(n-3). - R. J. Mathar, Mar 24 2018

A180753 Half the number of nX4 binary arrays with each element equal to at least two neighbors.

Original entry on oeis.org

0, 2, 2, 9, 21, 70, 207, 658, 2059, 6521, 20602, 65244, 206608, 654594, 2073996, 6571885, 20824917, 65991668, 209121585, 662691890, 2100031249, 6654888151, 21089009696, 66830061534, 211781324846, 671125181554, 2126764718766
Offset: 1

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Author

R. H. Hardin Sep 20 2010

Keywords

Comments

Column 4 of A180760

Formula

Empirical: a(n) = 5*a(n-1) - 6*a(n-2) + a(n-3) + a(n-4) - 9*a(n-5) + 4*a(n-6) + a(n-7) + 28*a(n-8) - 16*a(n-9) - 3*a(n-10) + 2*a(n-11) - 6*a(n-12) + 2*a(n-13) - a(n-14)

A180754 Half the number of nX5 binary arrays with each element equal to at least two neighbors.

Original entry on oeis.org

0, 3, 3, 21, 86, 410, 1874, 8840, 41755, 197883, 936625, 4434387, 20996674, 99434998, 470911050, 2230166446, 10561720749, 50018822099, 236882697591, 1121846953883, 5312927519916, 25161362888858, 119161085234850, 564332106834338
Offset: 1

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Author

R. H. Hardin Sep 20 2010

Keywords

Comments

Column 5 of A180760

Formula

Empirical: a(n) = 9*a(n-1) - 26*a(n-2) + 24*a(n-3) + 47*a(n-4) - 157*a(n-5) - 43*a(n-6) + 641*a(n-7) - 643*a(n-8) - 952*a(n-9) + 3460*a(n-10) - 2021*a(n-11) - 2111*a(n-12) + 2715*a(n-13) - 1249*a(n-14) - 4657*a(n-15) - 1514*a(n-16) + 1961*a(n-17) - 1230*a(n-18) + 6713*a(n-19) + 8832*a(n-20) + 10212*a(n-21) + 1971*a(n-22) - 6552*a(n-23) - 2819*a(n-24) - 2898*a(n-25) - 973*a(n-26) + 302*a(n-27) + 433*a(n-28) + 286*a(n-29)

A180755 Half the number of nX6 binary arrays with each element equal to at least two neighbors.

Original entry on oeis.org

0, 5, 7, 70, 410, 2986, 20205, 141313, 986376, 6925085, 48597819, 341209889, 2395331138, 16816717757, 118065063145, 828920971395, 5819799452720, 40860590480721, 286880736650848, 2014179680712444, 14141486042579555
Offset: 1

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Author

R. H. Hardin Sep 20 2010

Keywords

Comments

Column 6 of A180760

A180756 Half the number of nX7 binary arrays with each element equal to at least two neighbors.

Original entry on oeis.org

0, 8, 14, 207, 1874, 20205, 205020, 2141384, 22238670, 232041425, 2420128480, 25258683242, 263607333975, 2751296309311, 28715052573470, 299699771800630, 3127972672911502, 32646796609958085, 340736340129916559
Offset: 1

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Author

R. H. Hardin Sep 20 2010

Keywords

Comments

Column 7 of A180760

A180757 Half the number of nX8 binary arrays with each element equal to at least two neighbors.

Original entry on oeis.org

0, 13, 31, 658, 8840, 141313, 2141384, 33329847, 514990479, 7988200496, 123822198215, 1920693558801, 29793765165720, 462205529321051, 7170401050696078, 111238701384104135, 1725707750909016718
Offset: 1

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Author

R. H. Hardin Sep 20 2010

Keywords

Comments

Column 8 of A180760

A180758 Half the number of nX9 binary arrays with each element equal to at least two neighbors.

Original entry on oeis.org

0, 21, 67, 2059, 41755, 986376, 22238670, 514990479, 11843513563, 273193577866, 6295815062637, 145178091690740, 3347707869286493, 77204310077778551, 1780484848971706031, 41062118413701907548, 946988189894419322573
Offset: 1

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Author

R. H. Hardin Sep 20 2010

Keywords

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Column 9 of A180760

A180759 Half the number of nX10 binary arrays with each element equal to at least two neighbors.

Original entry on oeis.org

0, 34, 148, 6521, 197883, 6925085, 232041425, 7988200496, 273193577866, 9371551715962, 321126765178608, 11008960419802432, 377391950209233884, 12938484121557779809, 443585080271258369878, 15208220842498216076445
Offset: 1

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Author

R. H. Hardin Sep 20 2010

Keywords

Comments

Column 10 of A180760

A180751 Half the number of n X n binary arrays with each element equal to at least two neighbors.

Original entry on oeis.org

0, 1, 1, 9, 86, 2986, 205020, 33329847, 11843513563, 9371551715962, 16360949033733903
Offset: 1

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Author

R. H. Hardin Sep 20 2010

Keywords

Comments

Diagonal of A180760
Showing 1-9 of 9 results.