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 10 results.

A208638 Number of 3 X n 0..1 arrays with new values 0..1 introduced in row major order and no element equal to more than one of its immediate leftward or upward or right-upward antidiagonal neighbors.

Original entry on oeis.org

4, 13, 32, 71, 150, 309, 628, 1267, 2546, 5105, 10224, 20463, 40942, 81901, 163820, 327659, 655338, 1310697, 2621416, 5242855, 10485734, 20971493, 41943012, 83886051, 167772130, 335544289, 671088608, 1342177247, 2684354526, 5368709085
Offset: 1

Views

Author

R. H. Hardin, Feb 29 2012

Keywords

Comments

Row 3 of A208637. Possibly row 4 of the convolution array A213568. - Clark Kimberling, Jun 20 2012
From Noah Carey, Aug 31 2021: (Start)
Conjecture: a(n) is equal to half the sum along the edges of (centered, height 2, width n, starting at line n+1) rectangles in Pascal's triangle, as shown here for n=3 (not including the terms inside the rectangles):
1
1 1
1 2 1 a(3) = (4+6+4 + 15+20+15)/2
1 3 3 1
1 4---6---4 1
1 5 | | 5 1
1 6 15--20--15 6 1
1 7 21 35 35 20 7 1 (End)

Examples

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

Crossrefs

Cf. A208637.

Formula

Empirical: a(n) = 4*a(n-1) - 5*a(n-2) + 2*a(n-3).
Conjectures from Colin Barker, Mar 07 2018: (Start)
G.f.: x*(4 - 3*x) / ((1 - x)^2*(1 - 2*x)).
a(n) = 5*2^n - n - 5.
(End)

A208632 Number of n X n 0..1 arrays with new values 0..1 introduced in row major order and no element equal to more than one of its immediate leftward or upward or right-upward antidiagonal neighbors.

Original entry on oeis.org

1, 5, 32, 225, 1652, 12404, 94320, 722733, 5565560, 43005391, 333132384, 2585476348, 20097106512, 156418938680, 1218807197408, 9506457334965, 74216779041840, 579903491112365, 4534776883051800, 35488119754971345
Offset: 1

Views

Author

R. H. Hardin Feb 29 2012

Keywords

Comments

Diagonal of A208637

Examples

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

A208633 Number of n X 4 0..1 arrays with new values 0..1 introduced in row major order and no element equal to more than one of its immediate leftward or upward or right-upward antidiagonal neighbors.

Original entry on oeis.org

8, 23, 71, 225, 722, 2331, 7548, 24476, 79423, 257807, 836973, 2717446, 8823199, 28648292, 93019712, 302032007, 980690055, 3184277945, 10339281402, 33571429395, 109005736508, 353939387572, 1149233948207, 3731539152111
Offset: 1

Views

Author

R. H. Hardin, Feb 29 2012

Keywords

Comments

Column 4 of A208637.

Examples

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

Crossrefs

Cf. A208637.

Formula

Empirical: a(n) = 5*a(n-1) - 6*a(n-2) + a(n-3).
Empirical g.f.: x*(8 - 17*x + 4*x^2) / (1 - 5*x + 6*x^2 - x^3). - Colin Barker, Jul 05 2018

A208634 Number of n X 5 0..1 arrays with new values 0..1 introduced in row major order and no element equal to more than one of its immediate leftward or upward or right-upward antidiagonal neighbors.

Original entry on oeis.org

16, 47, 150, 494, 1652, 5572, 18888, 64216, 218704, 745616, 2543520, 8679776, 29625920, 101131840, 345250944, 1178690944, 4024163584, 13739075840, 46907582976, 160151393792, 546788836352, 1866849412096, 6373813684224
Offset: 1

Views

Author

R. H. Hardin, Feb 29 2012

Keywords

Comments

Column 5 of A208637.

Examples

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

Crossrefs

Cf. A208637.

Formula

Empirical: a(n) = 6*a(n-1) - 10*a(n-2) + 4*a(n-3).
Conjectures from Colin Barker, Jul 05 2018: (Start)
G.f.: x*(16 - 49*x + 28*x^2) / ((1 - 2*x)*(1 - 4*x + 2*x^2)).
a(n) = (3*2^(1+n) + (11-2*sqrt(2))*(2-sqrt(2))^n + (2+sqrt(2))^n*(11+2*sqrt(2))) / 4.
(End)

A208635 Number of n X 6 0..1 arrays with new values 0..1 introduced in row major order and no element equal to more than one of its immediate leftward or upward or right-upward antidiagonal neighbors.

Original entry on oeis.org

32, 95, 309, 1042, 3577, 12404, 43284, 151656, 532795, 1875161, 6607478, 23301225, 82215220, 290187784, 1024490960, 3617470935, 12774594765, 45114821146, 159335044937, 562751474084, 1987608261228, 7020221345560, 24795605196403
Offset: 1

Views

Author

R. H. Hardin, Feb 29 2012

Keywords

Comments

Column 6 of A208637.

Examples

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

Crossrefs

Cf. A208637.

Formula

Empirical: a(n) = 7*a(n-1) - 15*a(n-2) + 10*a(n-3) - a(n-4).
Empirical g.f.: x*(32 - 129*x + 124*x^2 - 16*x^3) / ((1 - x)*(1 - 6*x + 9*x^2 - x^3)). - Colin Barker, Jul 05 2018

A208636 Number of n X 7 0..1 arrays with new values 0..1 introduced in row major order and no element equal to more than one of its immediate leftward or upward or right-upward antidiagonal neighbors.

Original entry on oeis.org

64, 191, 628, 2149, 7504, 26508, 94320, 337227, 1209736, 4349981, 15668332, 56505640, 203961088, 736686999, 2662084284, 9622940853, 34793691400, 125826023972, 455089068016, 1646125164451, 5954682909712, 21541486064685
Offset: 1

Views

Author

R. H. Hardin, Feb 29 2012

Keywords

Comments

Column 7 of A208637.

Examples

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

Crossrefs

Cf. A208637.

Formula

Empirical: a(n) = 8*a(n-1) - 21*a(n-2) + 20*a(n-3) - 5*a(n-4).
Empirical g.f.: x*(64 - 321*x + 444*x^2 - 144*x^3) / ((1 - 3*x + x^2)*(1 - 5*x + 5*x^2)). - Colin Barker, Jul 05 2018

A208639 Number of 4 X n 0..1 arrays with new values 0..1 introduced in row major order and no element equal to more than one of its immediate leftward or upward or right-upward antidiagonal neighbors.

Original entry on oeis.org

8, 34, 95, 225, 494, 1042, 2149, 4375, 8840, 17784, 35687, 71509, 143170, 286510, 573209, 1146627, 2293484, 4587220, 9174715, 18349729, 36699782, 73399914, 146800205, 293600815, 587202064, 1174404592, 2348809679, 4697619885
Offset: 1

Views

Author

R. H. Hardin, Feb 29 2012

Keywords

Comments

Row 4 of A208637.

Examples

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

Crossrefs

Cf. A208637.

Formula

Empirical: a(n) = 5*a(n-1) - 9*a(n-2) + 7*a(n-3) - 2*a(n-4) for n>5.
Conjectures from Colin Barker, Jul 05 2018: (Start)
G.f.: x*(8 - 6*x - 3*x^2 + 2*x^4) / ((1 - x)^3*(1 - 2*x)).
a(n) = (-42 + 35*2^n - 13*n - n^2) / 2 for n>1.
(End)

A208640 Number of 5 X n 0..1 arrays with new values 0..1 introduced in row major order and no element equal to more than one of its immediate leftward or upward or right-upward antidiagonal neighbors.

Original entry on oeis.org

16, 89, 284, 722, 1652, 3577, 7504, 15448, 31440, 63543, 127884, 256718, 514556, 1030421, 2062360, 4126468, 8254936, 16512147, 33026868, 66056634, 132116516, 264236657, 528477344, 1056959152, 2113923232, 4227851887, 8455709724
Offset: 1

Views

Author

R. H. Hardin, Feb 29 2012

Keywords

Comments

Row 5 of A208637.

Examples

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

Crossrefs

Cf. A208637.

Formula

Empirical: a(n) = 6*a(n-1) - 14*a(n-2) + 16*a(n-3) - 9*a(n-4) + 2*a(n-5) for n>7.
Conjectures from Colin Barker, Jul 05 2018: (Start)
G.f.: x*(16 - 7*x - 26*x^2 + 8*x^3 + 16*x^4 - 2*x^5 - 4*x^6) / ((1 - x)^4*(1 - 2*x)).
a(n) = -84 + 63*2^n - (191*n)/6 - 4*n^2 - n^3/6 for n>2.
(End)

A208641 Number of 6 X n 0..1 arrays with new values 0..1 introduced in row major order and no element equal to more than one of its immediate leftward or upward or right-upward antidiagonal neighbors.

Original entry on oeis.org

32, 233, 851, 2331, 5572, 12404, 26508, 55260, 113427, 230559, 465773, 937321, 1881726, 3772054, 7554458, 15121266, 30257157, 60531513, 121083123, 242189591, 484406152, 968843304, 1937722072, 3875484536, 7751014887, 15502081539
Offset: 1

Views

Author

R. H. Hardin, Feb 29 2012

Keywords

Comments

Row 6 of A208637.

Examples

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

Crossrefs

Cf. A208637.

Formula

Empirical: a(n) = 7*a(n-1) - 20*a(n-2) + 30*a(n-3) - 25*a(n-4) + 11*a(n-5) - 2*a(n-6) for n>9.
Conjectures from Colin Barker, Jul 05 2018: (Start)
G.f.: x*(32 + 9*x - 140*x^2 + 74*x^3 + 85*x^4 - 37*x^5 - 34*x^6 + 4*x^7 + 8*x^8) / ((1 - x)^5*(1 - 2*x)).
a(n) = (792*(7*2^n-10) - 3382*n - 539*n^2 - 38*n^3 - n^4) / 24 for n>3.
(End)

A208642 Number of 7 X n 0..1 arrays with new values 0..1 introduced in row major order and no element equal to more than one of its immediate leftward or upward or right-upward antidiagonal neighbors.

Original entry on oeis.org

64, 610, 2552, 7548, 18888, 43284, 94320, 199299, 412962, 844943, 1714680, 3461238, 6962956, 13976742, 28016664, 56111133, 112317270, 224749641, 449637728, 899440872, 1799078160, 3598388200, 7197048672, 14394415431, 28789200714
Offset: 1

Views

Author

R. H. Hardin, Feb 29 2012

Keywords

Comments

Row 7 of A208637.

Examples

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

Crossrefs

Cf. A208637.

Formula

Empirical: a(n) = 8*a(n-1) - 27*a(n-2) + 50*a(n-3) - 55*a(n-4) + 36*a(n-5) - 13*a(n-6) + 2*a(n-7) for n>11.
Conjectures from Colin Barker, Jul 05 2018: (Start)
G.f.: x*(64 + 98*x - 600*x^2 + 402*x^3 + 428*x^4 - 378*x^5 - 144*x^6 + 77*x^7 + 78*x^8 - 8*x^9 - 16*x^10) / ((1 - x)^6*(1 - 2*x)).
a(n) = (51480*(-3+2^(1+n)) - 71394*n - 13145*n^2 - 1205*n^3 - 55*n^4 - n^5) / 120 for n>4.
(End)
Showing 1-10 of 10 results.