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.

A050974 Number of binary arrangements on n X n array without three adjacent 1's in a row or column.

Original entry on oeis.org

1, 2, 16, 265, 16561, 3157010, 1828904402, 3323590649777, 18691199385898465, 325778072452564800064, 17617718915229579206450786, 2954164381835835259001326344913, 1536134628973698280539373190731911729, 2477137610106747308204461168746042225266836, 12387488188151269567355592399321080831513078632498, 192102098800681202990688566451981906679020804069237862571, 9238409697848267958752630399467598421213391733838644131510525089
Offset: 0

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Author

Keywords

References

  • Steven R. Finch, Mathematical Constants, Cambridge, 2003, pp. 342-349.

Crossrefs

Any connected three 1's gives A067968.
Cf. A006506. Diagonal of A202471.

Programs

  • Mathematica
    t[m_] := t[m] = Map[ArrayReshape[#, {m, m}] &, Tuples[{0, 1}, m^2]]; a[m_] := a[m] = Count[Table[AnyTrue[Flatten[{Table[Equal[1, t[m][[n, a, b]], t[m][[n, a, b + 1]], t[m][[n, a, b + 2]]], {a, 1, m}, {b, 1, m - 2}], Table[Equal[1, t[m][[n, a, b]], t[m][[n, a + 1, b]], t[m][[n, a + 2, b]]], {a, 1, m - 2}, {b, 1, m}]}], TrueQ], {n, 1, 2^(m^2)}], False]; (* Robert P. P. McKone, Jan 04 2022 *)

Extensions

More terms from R. H. Hardin, Feb 02 2002
a(0)=1 prepended and a(13)-a(16) from Peter J. Taylor, Sep 26 2024

A202464 Number of (n+2) X 3 binary arrays with no more than two of any consecutive three bits set in any row or column.

Original entry on oeis.org

265, 1573, 9253, 54085, 317179, 1858993, 10894297, 63850777, 374215201, 2193190681, 12853833343, 75333557377, 441513844561, 2587618272973, 15165477047269, 88881616706701, 520916142332515, 3052978074328417
Offset: 1

Views

Author

R. H. Hardin, Dec 19 2011

Keywords

Comments

Column 1 of A202471.

Examples

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

Crossrefs

Cf. A202471.

Formula

Empirical: a(n) = 4*a(n-1) +8*a(n-2) +18*a(n-3) -6*a(n-4) +2*a(n-5) -a(n-6).
Empirical g.f.: x*(265 + 513*x + 841*x^2 - 281*x^3 + 91*x^4 - 49*x^5) / (1 - 4*x - 8*x^2 - 18*x^3 + 6*x^4 - 2*x^5 + x^6). - Colin Barker, Jun 01 2018

A202465 Number of (n+2)X4 binary arrays with no more than two of any consecutive three bits set in any row or column.

Original entry on oeis.org

1573, 16561, 172197, 1774281, 18374521, 190112777, 1966463785, 20345296193, 210482281689, 2177526620233, 22527699867037, 233060360137857, 2411126165020333, 24944324990455409, 258061639015145685
Offset: 1

Views

Author

R. H. Hardin Dec 19 2011

Keywords

Comments

Column 2 of A202471

Examples

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

Formula

Empirical: a(n) = 4*a(n-1) +36*a(n-2) +272*a(n-3) +350*a(n-4) +392*a(n-5) -3016*a(n-6) -164*a(n-7) -5522*a(n-8) +11427*a(n-9) -4608*a(n-10) +10140*a(n-11) -11817*a(n-12) +4108*a(n-13) -2432*a(n-14) +1176*a(n-15) -166*a(n-16) +124*a(n-17) -50*a(n-18) +4*a(n-19) -2*a(n-20) +a(n-21)

A202466 Number of (n+2)X5 binary arrays with no more than two of any consecutive three bits set in any row or column.

Original entry on oeis.org

9253, 172197, 3157010, 57262144, 1044865367, 19045287529, 347030298362, 6325139804762, 115276893817821, 2100921552416129, 38289856014452302, 697839603278397490, 12718251853368355369, 231792595465614884173
Offset: 1

Views

Author

R. H. Hardin Dec 19 2011

Keywords

Comments

Column 3 of A202471

Examples

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

Formula

Empirical: a(n) = 5*a(n-1) +111*a(n-2) +2014*a(n-3) +6557*a(n-4) +16985*a(n-5) -300395*a(n-6) -493842*a(n-7) -3268704*a(n-8) +24359757*a(n-9) -12644117*a(n-10) +245975711*a(n-11) -1125487262*a(n-12) +1522045563*a(n-13) -8087124133*a(n-14) +26777225059*a(n-15) -37534618180*a(n-16) +126433919538*a(n-17) -328489679534*a(n-18) +391815137702*a(n-19) -986011308148*a(n-20) +2122690461724*a(n-21) -1946484646192*a(n-22) +3965682502748*a(n-23) -7576159630469*a(n-24) +5031247471425*a(n-25) -9030564869781*a(n-26) +16603266615558*a(n-27) -7654100893731*a(n-28) +12605001997031*a(n-29) -23568791472338*a(n-30) +7284025623281*a(n-31) -11592415733849*a(n-32) +22376915552667*a(n-33) -4108143304538*a(n-34) +7534067585378*a(n-35) -14586401994989*a(n-36) +851438613707*a(n-37) -3651106111783*a(n-38) +6680505527134*a(n-39) +516890844951*a(n-40) +1330578342773*a(n-41) -2180316021478*a(n-42) -457849189081*a(n-43) -350426435259*a(n-44) +504531345207*a(n-45) +156767801632*a(n-46) +63587131764*a(n-47) -80543670710*a(n-48) -29202619778*a(n-49) -7801427038*a(n-50) +8520515392*a(n-51) +3153222478*a(n-52) +630256472*a(n-53) -563860143*a(n-54) -184231091*a(n-55) -26381427*a(n-56) +24372940*a(n-57) +5813919*a(n-58) +360687*a(n-59) -727057*a(n-60) -95650*a(n-61) +8776*a(n-62) +14851*a(n-63) +693*a(n-64) -335*a(n-65) -184*a(n-66) -a(n-67) +3*a(n-68) +a(n-69)

A202467 Number of (n+2)X6 binary arrays with no more than two of any consecutive three bits set in any row or column.

Original entry on oeis.org

54085, 1774281, 57262144, 1828904402, 58746383721, 1885066867201, 60472625443366, 1940390570621922, 62257900228006925, 1997548362431307729, 64092086253488512734, 2056411827878286085746, 65980528433359436484485
Offset: 1

Views

Author

R. H. Hardin Dec 19 2011

Keywords

Comments

Column 4 of A202471

Examples

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

A202468 Number of (n+2)X7 binary arrays with no more than two of any consecutive three bits set in any row or column.

Original entry on oeis.org

317179, 18374521, 1044865367, 58746383721, 3323590649777, 187820723381421, 10610932604054547, 599616560193259281, 33881738532796270907, 1914496303093962715299, 108180387260313623312899
Offset: 1

Views

Author

R. H. Hardin Dec 19 2011

Keywords

Comments

Column 5 of A202471

Examples

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

A202469 Number of (n+2) X 8 binary arrays with no more than two of any consecutive three bits set in any row or column.

Original entry on oeis.org

1858993, 190112777, 19045287529, 1885066867201, 187820723381421, 18691199385898465, 1859521153822030023, 185045901525934158257, 18413176084400451943067, 1832207303424558956985631
Offset: 1

Views

Author

R. H. Hardin, Dec 19 2011

Keywords

Comments

Column 6 of A202471.

Examples

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

Crossrefs

Cf. A202471.

A202470 Number of (n+2)X9 binary arrays with no more than two of any consecutive three bits set in any row or column.

Original entry on oeis.org

10894297, 1966463785, 347030298362, 60472625443366, 10610932604054547, 1859521153822030023, 325778072452564800064, 57089473505402700427612, 10003712847692227326534941, 1752925427213891417645669229
Offset: 1

Views

Author

R. H. Hardin Dec 19 2011

Keywords

Comments

Column 7 of A202471

Examples

			Some solutions for n=3
..0..0..0..0..0..0..1..1..0....0..0..0..0..0..0..0..0..1
..0..0..0..0..0..0..0..1..0....0..0..0..0..0..0..0..0..0
..0..0..0..0..0..0..0..0..1....0..0..0..0..0..0..0..1..0
..0..0..0..0..0..1..0..1..0....0..0..0..0..0..1..0..1..0
..0..0..0..0..0..0..1..0..1....0..0..0..0..0..0..0..0..0
		
Showing 1-8 of 8 results.