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 1-8 of 8 results.

A263053 Number of (n+1) X 2 0..1 arrays with each row and column not divisible by 3, read as a binary number with top and left being the most significant bits.

Original entry on oeis.org

2, 2, 10, 10, 42, 42, 170, 170, 682, 682, 2730, 2730, 10922, 10922, 43690, 43690, 174762, 174762, 699050, 699050, 2796202, 2796202, 11184810, 11184810, 44739242, 44739242, 178956970, 178956970, 715827882, 715827882, 2863311530, 2863311530
Offset: 1

Views

Author

R. H. Hardin, Oct 08 2015

Keywords

Comments

Each row must be either 01 or 10. The two columns are therefore binary complements with sum 2^k-1, where k = n + 1 is the number of rows. If k is even then 2^k-1 is divisible by 3 and the number of solutions is 2*(2^k-1)/3. If k is odd then 2^k-1 == 1 (mod 3) and the number of solutions is (2^k-2)/3. - Andrew Howroyd, Feb 03 2022

Examples

			All solutions for n=4:
  0 1   0 1   1 0   1 0   1 0   0 1   1 0   1 0   0 1   0 1
  0 1   0 1   0 1   1 0   0 1   1 0   1 0   0 1   1 0   1 0
  1 0   0 1   0 1   1 0   1 0   1 0   0 1   1 0   0 1   0 1
  0 1   1 0   0 1   0 1   1 0   1 0   1 0   0 1   1 0   0 1
  1 0   0 1   1 0   1 0   1 0   0 1   0 1   0 1   1 0   0 1
		

Crossrefs

Column 1 of A263060.
Cf. A052992.

Programs

  • Python
    [int(2**n - 2/3 -((-2)**n)/3) for n in range(1,40)] # Pascal Bisson, Feb 03 2022

Formula

a(n) = a(n-1) + 4*a(n-2) - 4*a(n-3).
From Colin Barker, Jan 01 2019: (Start)
G.f.: 2*x / ((1 - x)*(1 - 2*x)*(1 + 2*x)).
a(n) = 2^n - 2/3 - (-2)^n/3.
(End)
a(n) = 2*A052992(n). - Pascal Bisson, Feb 03 2022

A263052 Number of (n+1)X(n+1) 0..1 arrays with each row and column not divisible by 3, read as a binary number with top and left being the most significant bits.

Original entry on oeis.org

2, 33, 1666, 498597, 439260642, 1825928130193, 26380510465997186, 1607516667474074649381, 373842629115554331580791202, 353418497958270475251697468005873
Offset: 1

Views

Author

R. H. Hardin, Oct 08 2015

Keywords

Comments

Diagonal of A263060.

Examples

			Some solutions for n=3
..1..0..1..1....1..0..0..0....0..1..0..1....1..0..1..1....1..0..1..1
..0..1..0..0....0..1..1..1....0..0..1..0....0..0..0..1....0..1..0..1
..1..0..1..1....1..0..1..0....0..1..0..1....1..0..1..1....0..1..1..1
..0..0..1..0....1..0..1..1....1..1..1..0....1..1..1..0....0..1..0..0
		

Crossrefs

Cf. A263060.

A263054 Number of (n+1) X (2+1) 0..1 arrays with each row and column not divisible by 3, read as a binary number with top and left being the most significant bits.

Original entry on oeis.org

2, 33, 142, 895, 4314, 22921, 113486, 577071, 2877562, 14455993, 72225582, 361607935, 1807659674, 9041669481, 45205690126, 226052092111, 1130241870522, 5651375017753, 28256745002222, 141284885366175, 706423516399834
Offset: 1

Views

Author

R. H. Hardin, Oct 08 2015

Keywords

Examples

			Some solutions for n=4:
..1..0..1....0..0..1....1..0..0....1..0..0....1..0..1....1..0..1....1..0..0
..1..1..1....1..0..0....0..1..0....0..1..0....1..0..1....0..0..1....1..0..1
..1..1..1....1..1..1....1..1..1....0..1..0....0..0..1....1..1..1....0..1..0
..1..1..1....0..0..1....1..0..0....0..1..0....0..1..0....1..0..0....0..0..1
..1..0..1....1..1..1....0..1..0....1..0..1....1..0..0....0..0..1....1..1..1
		

Crossrefs

Column 2 of A263060.

Formula

Empirical: a(n) = 5*a(n-1) + 12*a(n-2) - 60*a(n-3) - 39*a(n-4) + 195*a(n-5) + 28*a(n-6) - 140*a(n-7).
Empirical g.f.: x*(2 + 23*x - 47*x^2 - 91*x^3 + 193*x^4 + 28*x^5 - 140*x^6) / ((1 - x)*(1 + x)*(1 - 2*x)*(1 + 2*x)*(1 - 5*x)*(1 - 7*x^2)). - Colin Barker, Jan 01 2019

A263055 Number of (n+1)X(3+1) 0..1 arrays with each row and column not divisible by 3, read as a binary number with top and left being the most significant bits.

Original entry on oeis.org

10, 142, 1666, 18390, 188370, 1941702, 19499266, 196698070, 1968558130, 19732383462, 197355588066, 1974792933750, 19748600169490, 197518001324422, 1975194815632066, 19752765325169430, 197527991815422450
Offset: 1

Views

Author

R. H. Hardin, Oct 08 2015

Keywords

Comments

Column 3 of A263060.

Examples

			Some solutions for n=4
..1..0..1..0....1..1..1..0....1..1..0..1....1..1..0..1....1..0..1..1
..1..1..0..1....0..1..1..1....0..0..1..0....0..0..0..1....0..1..0..1
..1..0..1..0....0..1..1..1....0..0..0..1....1..0..1..1....0..0..1..0
..0..0..1..0....0..0..0..1....1..0..1..0....1..0..0..0....1..1..0..1
..1..0..0..0....1..0..1..0....1..0..0..0....1..0..1..1....1..0..0..0
		

Crossrefs

Cf. A263060.

Formula

Empirical: a(n) = 11*a(n-1) +35*a(n-2) -495*a(n-3) -114*a(n-4) +6204*a(n-5) -4040*a(n-6) -17600*a(n-7) +16000*a(n-8)

A263056 Number of (n+1)X(4+1) 0..1 arrays with each row and column not divisible by 3, read as a binary number with top and left being the most significant bits.

Original entry on oeis.org

10, 895, 18390, 498597, 10416690, 232738767, 4880746710, 104100946101, 2185333961490, 46071984907935, 967423105276470, 20335923462641157, 427044510774483570, 8970161111918918127, 188372284635598141590
Offset: 1

Views

Author

R. H. Hardin, Oct 08 2015

Keywords

Comments

Column 4 of A263060.

Examples

			Some solutions for n=3
..1..0..0..1..1....0..0..0..1..0....0..0..1..1..1....0..0..0..0..1
..0..0..1..0..0....1..1..0..0..1....1..1..0..0..1....1..0..1..0..0
..1..1..0..1..0....1..1..1..0..0....0..1..0..1..1....0..1..1..1..0
..0..0..0..1..0....1..1..0..0..1....0..1..0..1..0....1..0..1..0..0
		

Crossrefs

Cf. A263060.

Formula

Empirical: a(n) = 21*a(n-1) +189*a(n-2) -3969*a(n-3) -10719*a(n-4) +225099*a(n-5) +250803*a(n-6) -5266863*a(n-7) -2527200*a(n-8) +53071200*a(n-9) +9062928*a(n-10) -190321488*a(n-11)

A263057 Number of (n+1)X(5+1) 0..1 arrays with each row and column not divisible by 3, read as a binary number with top and left being the most significant bits.

Original entry on oeis.org

42, 4314, 188370, 10416690, 439260642, 19763462754, 830550961170, 35491321238130, 1490799705490242, 62885673930539394, 2641262874276464370, 111053568381384471570, 4664277162998698135842, 195952869163413914931234
Offset: 1

Views

Author

R. H. Hardin, Oct 08 2015

Keywords

Comments

Column 5 of A263060.

Examples

			Some solutions for n=3
..0..1..0..0..1..1....0..1..1..0..1..0....0..1..1..0..0..1....0..1..1..0..0..1
..1..0..0..0..0..0....1..0..1..1..1..0....1..0..1..0..0..0....1..0..0..0..1..0
..1..1..0..1..1..1....1..0..0..0..1..1....0..1..0..1..1..1....1..1..1..1..1..0
..1..0..1..0..0..1....1..0..1..1..0..0....0..1..1..0..0..1....1..1..1..0..1..0
		

Crossrefs

Cf. A263060.

Formula

Empirical: a(n) = 42*a(n-1) +711*a(n-2) -29862*a(n-3) -141183*a(n-4) +5929686*a(n-5) +10349613*a(n-6) -434683746*a(n-7) -267400116*a(n-8) +11230804872*a(n-9) +1666598976*a(n-10) -69997156992*a(n-11)

A263058 Number of (n+1)X(6+1) 0..1 arrays with each row and column not divisible by 3, read as a binary number with top and left being the most significant bits.

Original entry on oeis.org

42, 22921, 1941702, 232738767, 19763462754, 1825928130193, 155157177242886, 13464303796343791, 1144373527121975682, 97776065732064546321, 8310794250378741921702, 707331447947977777389487
Offset: 1

Views

Author

R. H. Hardin, Oct 08 2015

Keywords

Comments

Column 6 of A263060.

Examples

			Some solutions for n=2
..1..0..0..1..1..0..0....1..0..0..0..0..1..1....0..0..1..1..1..0..1
..1..0..0..0..1..1..1....0..1..0..1..0..0..0....1..0..1..1..0..0..0
..1..1..1..1..1..0..0....0..0..1..0..1..0..0....0..1..1..1..0..1..1
		

Crossrefs

Cf. A263060.

Formula

Empirical: a(n) = 85*a(n-1) +3026*a(n-2) -257210*a(n-3) -2725780*a(n-4) +231691300*a(n-5) +1042604066*a(n-6) -88621345610*a(n-7) -184834243867*a(n-8) +15710910728695*a(n-9) +16148556399500*a(n-10) -1372627293957500*a(n-11) -690707626945552*a(n-12) +58710148290371920*a(n-13) +13366198928883008*a(n-14) -1136126908955055680*a(n-15) -92117546962355200*a(n-16) +7829991491800192000*a(n-17)

A263059 Number of (n+1)X(7+1) 0..1 arrays with each row and column not divisible by 3, read as a binary number with top and left being the most significant bits.

Original entry on oeis.org

170, 113486, 19499266, 4880746710, 830550961170, 155157177242886, 26380510465997186, 4591006241105432150, 780492175300947773170, 133462112418824638334886, 22688696181791779887035106
Offset: 1

Views

Author

R. H. Hardin, Oct 08 2015

Keywords

Comments

Column 7 of A263060.

Examples

			Some solutions for n=2
..1..0..1..1..1..1..1..1....1..0..0..0..1..1..1..1....1..1..0..1..0..1..1..0
..1..0..1..0..0..0..0..1....0..0..1..1..0..0..1..0....0..1..0..0..1..1..0..0
..1..1..1..1..1..1..0..1....1..1..0..0..0..0..1..0....0..1..1..0..0..1..1..1
		

Crossrefs

Cf. A263060.

Formula

Empirical: a(n) = 170*a(n-1) +12088*a(n-2) -2054960*a(n-3) -43463646*a(n-4) +7388819820*a(n-5) +66398454660*a(n-6) -11287737292200*a(n-7) -47263888640505*a(n-8) +8034861068885850*a(n-9) +16948827007298316*a(n-10) -2881300591240713720*a(n-11) -3142452853334937648*a(n-12) +534216985066939400160*a(n-13) +298488023933669046336*a(n-14) -50742964068723737877120*a(n-15) -13934074238604397209600*a(n-16) +2368792620562747525632000*a(n-17) +287178122770920663040000*a(n-18) -48820280871056512716800000*a(n-19) -2061386929701535744000000*a(n-20) +350435778049261076480000000*a(n-21)
Showing 1-8 of 8 results.