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 1-10 of 11 results. Next

A230699 Sequence of pairs k,g such that k*2^n-1, k*2^n-1+g, k*2^n-1+2*g, and k*2^n+3*g are four consecutive primes in arithmetic progression for the smallest odd k.

Original entry on oeis.org

135, -6, 63, 6, 415, -6, 987, 6, 55, -6, 273, 6, 1195, -6, 299, 18, 1371, 6, 5, -6, 189, 6, 1077, 6, 7111, 6, 15, -6, 2821, -18, 15465, 24, 1081, 6, 11475, -6, 17155, -6, 3393, 12, 9751, 6, 16523, -24, 165, -6, 7395, -6, 8695, -6, 20325, -6, 7153, 18, 2235, -6
Offset: 1

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Author

Pierre CAMI, Oct 30 2013

Keywords

Comments

The number g may be negative.
g is always 0 mod 6 so a multiple of 6.

Examples

			135*2^1-1=269, 135*2^1-1-6=263, 135*2^1-1-2*6=257, 135*2^1-1-3*6=251
269, 263, 257, 251 are four consecutive primes in arithmetic progression so a(1)=135, a(2)=-6.
63*2^2-1=251, 63*2^2-1+6=257, 63*2^2-1+2*6=263, 63*2^2-1-3*6=269
251, 257, 263, 269 are four consecutive primes in arithmetic progression so a(3)=63 a(4)=6.
		

Crossrefs

A228749 Number of n X n binary arrays with top left element equal to 1 and no two ones adjacent horizontally or antidiagonally.

Original entry on oeis.org

1, 3, 39, 780, 43862, 4823826, 1316714732, 762713002760, 1040109467257908, 3118624187066762728, 21501868781585259257676, 331091404725670052219822756, 11603262095526618070600084170304, 914315533886530112431287075923892544
Offset: 1

Views

Author

R. H. Hardin Sep 02 2013

Keywords

Comments

Diagonal of A228754

Examples

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

A228750 Number of n X 4 binary arrays with top left element equal to 1 and no two ones adjacent horizontally or antidiagonally.

Original entry on oeis.org

3, 20, 126, 780, 4808, 29608, 182288, 1122240, 6908896, 42533440, 261849728, 1612032128, 9924194048, 61096565760, 376130326016, 2315580595200, 14255467112448, 87761291061248, 540287045521408, 3326182739886080
Offset: 1

Views

Author

R. H. Hardin, Sep 02 2013

Keywords

Examples

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

Crossrefs

Column 4 of A228754.

Formula

Empirical: a(n) = 8*a(n-1) - 12*a(n-2) + 4*a(n-3).
Empirical g.f.: x*(3 - 4*x + 2*x^2) / (1 - 8*x + 12*x^2 - 4*x^3). - Colin Barker, Sep 12 2018

A228751 Number of n X 5 binary arrays with top left element equal to 1 and no two ones adjacent horizontally or antidiagonally.

Original entry on oeis.org

5, 50, 482, 4599, 43862, 418370, 3990739, 38067290, 363121586, 3463797759, 33040991486, 315176359538, 3006451507579, 28678390419458, 273561730649282, 2609491655262279, 24891810279661862, 237441732282894050
Offset: 1

Views

Author

R. H. Hardin, Sep 02 2013

Keywords

Examples

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

Crossrefs

Column 5 of A228754.

Formula

Empirical: a(n) = 13*a(n-1) - 36*a(n-2) + 29*a(n-3) - 5*a(n-4) for n>5.
Empirical g.f.: x*(5 - 15*x + 12*x^2 - 12*x^3 + 2*x^4) / ((1 - x)*(1 - 12*x + 24*x^2 - 5*x^3)). - Colin Barker, Sep 12 2018

A228752 Number of n X 6 binary arrays with top left element equal to 1 and no two ones adjacent horizontally or antidiagonally.

Original entry on oeis.org

8, 119, 1712, 24246, 342207, 4823826, 67970044, 957616341, 13491214832, 190066959598, 2677695197199, 37723794440794, 531458704862804, 7487272853619205, 105481862639606840, 1486044856081515654
Offset: 1

Views

Author

R. H. Hardin, Sep 02 2013

Keywords

Examples

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

Crossrefs

Column 6 of A228754.

Formula

Empirical: a(n) = 21*a(n-1) - 112*a(n-2) + 217*a(n-3) - 157*a(n-4) + 36*a(n-5) for n>6.
Empirical g.f.: x*(8 - 49*x + 109*x^2 - 114*x^3 + 218*x^4 - 78*x^5) / (1 - 21*x + 112*x^2 - 217*x^3 + 157*x^4 - 36*x^5). - Colin Barker, Sep 12 2018

A228753 Number of nX7 binary arrays with top left element equal to 1 and no two ones adjacent horizontally or antidiagonally.

Original entry on oeis.org

13, 289, 6277, 134440, 2876170, 61534448, 1316714732, 28177227352, 602998827928, 12904414518912, 276160275058160, 5909958226524512, 126475877308730464, 2706643227463513344, 57923438257867988416, 1239588830689830585216
Offset: 1

Views

Author

R. H. Hardin Sep 02 2013

Keywords

Comments

Column 7 of A228754

Examples

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

Formula

Empirical: a(n) = 34*a(n-1) -324*a(n-2) +1264*a(n-3) -2236*a(n-4) +1816*a(n-5) -624*a(n-6) +64*a(n-7) for n>9

A228755 Number of 3 X n binary arrays with top left element equal to 1 and no two ones adjacent horizontally or antidiagonally.

Original entry on oeis.org

4, 8, 39, 126, 482, 1712, 6277, 22700, 82580, 299648, 1088499, 3952186, 14352786, 52119040, 189266297, 687294648, 2495834292, 9063317432, 32912374319, 119517358582, 434013128786, 1576067091632, 5723300581661, 20783486354532
Offset: 1

Views

Author

R. H. Hardin, Sep 02 2013

Keywords

Examples

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

Crossrefs

Row 3 of A228754.

Formula

Empirical: a(n) = 2*a(n-1) + 6*a(n-2) - a(n-4).
Empirical g.f.: x*(2 - x)*(2 + x) / (1 - 2*x - 6*x^2 + x^4). - Colin Barker, Sep 12 2018

A228756 Number of 4 X n binary arrays with top left element equal to 1 and no two ones adjacent horizontally or antidiagonally.

Original entry on oeis.org

8, 21, 168, 780, 4599, 24246, 134440, 728537, 3988862, 21739002, 118720559, 647758554, 3535719686, 19295840383, 105313615878, 574764393110, 3136909949941, 17120293581344, 93437607513222, 509954720089427
Offset: 1

Views

Author

R. H. Hardin, Sep 02 2013

Keywords

Examples

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

Crossrefs

Row 4 of A228754.

Formula

Empirical: a(n) = a(n-1) + 20*a(n-2) + 27*a(n-3) - 14*a(n-4) - 25*a(n-5) + 4*a(n-6) + 5*a(n-7) - a(n-8).
Empirical g.f.: x*(8 + 13*x - 13*x^2 - 24*x^3 + 4*x^4 + 5*x^5 - x^6) / ((1 + x)*(1 + 2*x - x^2)*(1 - 4*x - 9*x^2 + 5*x^3 + 4*x^4 - x^5)). - Colin Barker, Sep 13 2018

A228757 Number of 5Xn binary arrays with top left element equal to 1 and no two ones adjacent horizontally or antidiagonally.

Original entry on oeis.org

16, 55, 723, 4808, 43862, 342207, 2876170, 23326164, 192379841, 1574217212, 12928573892, 106000461919, 869759215471, 7134075563384, 58525595955046, 480089753747591, 3938341082031018, 32307082900690396, 265023929648410933
Offset: 1

Views

Author

R. H. Hardin Sep 02 2013

Keywords

Comments

Row 5 of A228754

Examples

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

Formula

Empirical: a(n) = a(n-1) +49*a(n-2) +107*a(n-3) -154*a(n-4) -404*a(n-5) +250*a(n-6) +472*a(n-7) -278*a(n-8) -168*a(n-9) +131*a(n-10) -9*a(n-11) -7*a(n-12) +a(n-13)

A228758 Number of 6Xn binary arrays with top left element equal to 1 and no two ones adjacent horizontally or antidiagonally.

Original entry on oeis.org

32, 144, 3111, 29608, 418370, 4823826, 61534448, 746135864, 9275632316, 113914525214, 1407229306722, 17335288371612, 213833281859269, 2636011878793640, 32504748521697000, 400762354405626468
Offset: 1

Views

Author

R. H. Hardin Sep 02 2013

Keywords

Comments

Row 6 of A228754

Examples

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

Formula

Empirical: a(n) = a(n-1) +119*a(n-2) +397*a(n-3) -1395*a(n-4) -5213*a(n-5) +8797*a(n-6) +24443*a(n-7) -36756*a(n-8) -45888*a(n-9) +84092*a(n-10) +19388*a(n-11) -83412*a(n-12) +24912*a(n-13) +22741*a(n-14) -12257*a(n-15) -1459*a(n-16) +1607*a(n-17) -49*a(n-18) -71*a(n-19) +3*a(n-20) +a(n-21)
Showing 1-10 of 11 results. Next