A057960
Number of base-5 (n+1)-digit numbers starting with a zero and with adjacent digits differing by one or less.
Original entry on oeis.org
1, 2, 5, 13, 35, 95, 259, 707, 1931, 5275, 14411, 39371, 107563, 293867, 802859, 2193451, 5992619, 16372139, 44729515, 122203307, 333865643, 912137899, 2492007083, 6808289963, 18600594091, 50817768107, 138836724395, 379308985003, 1036291418795, 2831200807595
Offset: 0
a(6) = 259 since a(5) = 21 + 30 + 25 + 14 + 5 so a(6) = (21+30) + (21 + 30 + 25) + (30+25+14) + (25+14+5) + (14+5) = 51 + 76 + 69 + 44 + 19.
- Vincenzo Librandi, Table of n, a(n) for n = 0..1000
- Jean-Luc Baril, Sergey Kirgizov, and Vincent Vajnovszki, Descent distribution on Catalan words avoiding a pattern of length at most three, arXiv:1803.06706 [math.CO], 2018.
- Tomislav Došlić and Biserka Kolarec, On Log-Definite Tempered Combinatorial Sequences, Mathematics (2025) Vol. 13, Iss. 7, 1179.
- Arnold Knopfmacher, Toufik Mansour, Augustine Munagi, and Helmut Prodinger, Smooth words and Chebyshev polynomials, arXiv:0809.0551v1 [math.CO], 2008.
- Index entries for linear recurrences with constant coefficients, signature (3,0,-2).
The "three-choice" comes in the recurrence b(n+1, i) = b(n, i-1) + b(n, i) + b(n, i+1) if 1 <= i <= 5. Narrower corridors produce
A000012,
A000079,
A000129,
A001519. An infinitely wide corridor (i.e., just one wall) would produce
A005773. Two-choice corridors are
A000124,
A000125,
A000127.
-
with(combstruct): ZL0:=S=Prod(Sequence(Prod(a, Sequence(b))), b): ZL1:=Prod(begin_blockP, Z, end_blockP): ZL2:=Prod(begin_blockLR, Z, Sequence(Prod(mu_length, Z), card>=1), end_blockLR): ZL3:=Prod(begin_blockRL, Sequence(Prod(mu_length, Z), card>=1), Z, end_blockRL):Q:=subs([a=Union(ZL1, ZL2, ZL3), b=ZL3], ZL0), begin_blockP=Epsilon, end_blockP=Epsilon, begin_blockLR=Epsilon, end_blockLR=Epsilon, begin_blockRL=Epsilon, end_blockRL=Epsilon, mu_length=Epsilon:temp15:=draw([S, {Q}, unlabelled], size=15):seq(count([S, {Q}, unlabelled], size=n+2), n=0..28); # Zerinvary Lajos, Mar 08 2008
-
Join[{a=1,b=2},Table[c=(a+b)*2-1;a=b;b=c,{n,0,50}]] (* Vladimir Joseph Stephan Orlovsky, Nov 22 2010 *)
CoefficientList[Series[(1-x-x^2)/((1-x)*(1-2*x-2*x^2)),{x,0,100}],x] (* Vincenzo Librandi, Aug 13 2012 *)
-
from functools import cache
@cache
def B(n, j):
if not 0 <= j < 5:
return 0
if n == 0:
return j == 0
return B(n - 1, j - 1) + B(n - 1, j) + B(n - 1, j + 1)
def A057960(n):
return sum(B(n, j) for j in range(5))
print([A057960(n) for n in range(30)]) # Pontus von Brömssen, Sep 06 2021
A220062
Number A(n,k) of n length words over k-ary alphabet, where neighboring letters are neighbors in the alphabet; square array A(n,k), n>=0, k>=0, read by antidiagonals.
Original entry on oeis.org
1, 1, 0, 1, 1, 0, 1, 2, 0, 0, 1, 3, 2, 0, 0, 1, 4, 4, 2, 0, 0, 1, 5, 6, 6, 2, 0, 0, 1, 6, 8, 10, 8, 2, 0, 0, 1, 7, 10, 14, 16, 12, 2, 0, 0, 1, 8, 12, 18, 24, 26, 16, 2, 0, 0, 1, 9, 14, 22, 32, 42, 42, 24, 2, 0, 0, 1, 10, 16, 26, 40, 58, 72, 68, 32, 2, 0, 0
Offset: 0
A(5,3) = 12: there are 12 words of length 5 over 3-ary alphabet {a,b,c}, where neighboring letters are neighbors in the alphabet: ababa, ababc, abcba, abcbc, babab, babcb, bcbab, bcbcb, cbaba, cbabc, cbcba, cbcbc.
Square array A(n,k) begins:
1, 1, 1, 1, 1, 1, 1, 1, ...
0, 1, 2, 3, 4, 5, 6, 7, ...
0, 0, 2, 4, 6, 8, 10, 12, ...
0, 0, 2, 6, 10, 14, 18, 22, ...
0, 0, 2, 8, 16, 24, 32, 40, ...
0, 0, 2, 12, 26, 42, 58, 74, ...
0, 0, 2, 16, 42, 72, 104, 136, ...
0, 0, 2, 24, 68, 126, 188, 252, ...
Columns k=0, 2-10 give:
A000007,
A040000,
A029744(n+2) for n>0,
A006355(n+3) for n>0,
A090993(n+1) for n>0,
A090995(n-1) for n>2,
A129639,
A153340,
A153362,
A153360.
-
b:= proc(n, i, k) option remember; `if`(n=0, 1,
`if`(i=0, add(b(n-1, j, k), j=1..k),
`if`(i>1, b(n-1, i-1, k), 0)+
`if`(i b(n, 0, k):
seq(seq(A(n, d-n), n=0..d), d=0..14);
-
b[n_, i_, k_] := b[n, i, k] = If[n == 0, 1, If[i == 0, Sum[b[n-1, j, k], {j, 1, k}], If[i>1, b[n-1, i-1, k], 0] + If[iJean-François Alcover, Jan 19 2015, after Alois P. Heinz *)
-
TransferGf(m,u,t,v,z)=vector(m,i,u(i))*matsolve(matid(m)-z*matrix(m,m,i,j,t(i,j)),vectorv(m,i,v(i)));
ColGf(m,z)=1+z*TransferGf(m, i->1, (i,j)->abs(i-j)==1, j->1, z);
a(n,k)=Vec(ColGf(k,x) + O(x^(n+1)))[n+1];
for(n=0, 7, for(k=0, 7, print1( a(n,k), ", ") ); print(); );
\\ Andrew Howroyd, Apr 17 2017
A276562
Array read by antidiagonals: T(m,n) = number of m-ary words of length n with cyclically adjacent elements differing by 1 or less.
Original entry on oeis.org
1, 1, 2, 1, 4, 3, 1, 8, 7, 4, 1, 16, 15, 10, 5, 1, 32, 35, 22, 13, 6, 1, 64, 83, 54, 29, 16, 7, 1, 128, 199, 134, 73, 36, 19, 8, 1, 256, 479, 340, 185, 92, 43, 22, 9, 1, 512, 1155, 872, 481, 236, 111, 50, 25, 10, 1, 1024, 2787, 2254, 1265, 622, 287, 130, 57, 28, 11
Offset: 1
Array starts:
1 1 1 1 1 1 1 1 1 1 ...
2 4 8 16 32 64 128 256 512 1024 ...
3 7 15 35 83 199 479 1155 2787 6727 ...
4 10 22 54 134 340 872 2254 5854 15250 ...
5 13 29 73 185 481 1265 3361 8993 24193 ...
6 16 36 92 236 622 1658 4468 12132 33146 ...
7 19 43 111 287 763 2051 5575 15271 42099 ...
8 22 50 130 338 904 2444 6682 18410 51052 ...
9 25 57 149 389 1045 2837 7789 21549 60005 ...
10 28 64 168 440 1186 3230 8896 24688 68958 ...
-
T[m_, n_] := Sum[(1 + 2*Cos[j*Pi/(m+1)])^n, {j, 1, m}] // FullSimplify;
Table[T[m-n+1, n], {m, 1, 11}, {n, m, 1, -1}] // Flatten (* Jean-François Alcover, Jun 06 2017 *)
-
\\ from Knopfmacher et al.
ChebyshevU(n,x) = sum(i=0, n/2, 2*poltchebi(n-2*i,x)) + (n%2-1);
RowGf(k,x) = 1 + (k*x*(1+3*x) - 2*(k+1)*x*subst(ChebyshevU(k-1,z)/ChebyshevU(k,z),z,(1-x)/(2*x)))/((1+x)*(1-3*x));
a(m,n)=Vec(RowGf(m,x)+O(x^(n+1)))[n+1];
for(m=1, 10, print(RowGf(m,x)));
for(m=1, 10, for(n=1, 9, print1( a(m,n), ", ") ); print(); );
A188861
Number of n X 4 binary arrays without the pattern 0 1 diagonally, vertically or antidiagonally.
Original entry on oeis.org
16, 41, 68, 95, 122, 149, 176, 203, 230, 257, 284, 311, 338, 365, 392, 419, 446, 473, 500, 527, 554, 581, 608, 635, 662, 689, 716, 743, 770, 797, 824, 851, 878, 905, 932, 959, 986, 1013, 1040, 1067, 1094, 1121, 1148, 1175, 1202, 1229, 1256, 1283, 1310, 1337, 1364
Offset: 1
Some solutions for 3 X 4:
..1..1..1..1....1..1..0..1....1..1..1..1....1..0..1..1....1..1..1..1
..1..1..1..1....0..0..0..0....1..1..1..0....0..0..0..0....0..0..1..0
..1..0..0..1....0..0..0..0....1..1..0..0....0..0..0..0....0..0..0..0
A285266
Array read by antidiagonals: T(m,n) = number of m-ary words of length n with adjacent elements differing by 2 or less.
Original entry on oeis.org
1, 3, 1, 9, 4, 1, 27, 14, 5, 1, 81, 50, 19, 6, 1, 243, 178, 75, 24, 7, 1, 729, 634, 295, 100, 29, 8, 1, 2187, 2258, 1161, 418, 125, 34, 9, 1, 6561, 8042, 4569, 1748, 543, 150, 39, 10, 1, 19683, 28642, 17981, 7310, 2363, 668, 175, 44, 11, 1
Offset: 3
Array starts (m>=3, n>=0):
1 3 9 27 81 243 729 2187 6561 ...
1 4 14 50 178 634 2258 8042 28642 ...
1 5 19 75 295 1161 4569 17981 70763 ...
1 6 24 100 418 1748 7310 30570 127842 ...
1 7 29 125 543 2363 10287 44787 194995 ...
1 8 34 150 668 2986 13362 59816 267802 ...
1 9 39 175 793 3611 16475 75229 343633 ...
1 10 44 200 918 4236 19598 90790 420870 ...
-
diff = 2; m0 = 3; mmax = 12;
TransferGf[m_, u_, t_, v_, z_] := Array[u, m].LinearSolve[IdentityMatrix[m] - z*Array[t, {m, m}], Array[v, m]]
RowGf[d_, m_, z_] := 1+z*TransferGf[m, 1&, Boole[Abs[#1-#2] <= d]&, 1&, z];
row[m_] := row[m] = CoefficientList[RowGf[diff, m, x] + O[x]^mmax, x];
T[m_ /; m >= m0, n_ /; n >= 0] := row[m][[n + 1]];
Table[T[m - n , n], {m, m0, mmax}, {n, m - m0, 0, -1}] // Flatten (* Jean-François Alcover, Jun 17 2017, adapted from PARI *)
-
TransferGf(m,u,t,v,z)=vector(m,i,u(i))*matsolve(matid(m)-z*matrix(m,m,i,j,t(i,j)),vectorv(m,i,v(i)));
RowGf(d,m,z)=1+z*TransferGf(m, i->1, (i,j)->abs(i-j)<=d, j->1, z);
for(m=3, 10, print(RowGf(2,m,x)));
for(m=3, 10, v=Vec(RowGf(2,m,x) + O(x^9)); for(n=1, length(v), print1( v[n], ", ") ); print(); );
A285267
Array read by antidiagonals: T(m,n) = number of m-ary words of length n with adjacent elements differing by 3 or less.
Original entry on oeis.org
1, 4, 1, 16, 5, 1, 64, 23, 6, 1, 256, 107, 30, 7, 1, 1024, 497, 154, 37, 8, 1, 4096, 2309, 788, 203, 44, 9, 1, 16384, 10727, 4034, 1111, 252, 51, 10, 1, 65536, 49835, 20650, 6083, 1446, 301, 58, 11, 1, 262144, 231521, 105708, 33305, 8300, 1787, 350, 65, 12, 1
Offset: 4
Array starts (m>=4, n>=0):
1 4 16 64 256 1024 4096 16384 ...
1 5 23 107 497 2309 10727 49835 ...
1 6 30 154 788 4034 20650 105708 ...
1 7 37 203 1111 6083 33305 182349 ...
1 8 44 252 1446 8300 47642 273466 ...
1 9 51 301 1787 10619 63111 375091 ...
1 10 58 350 2130 12990 79258 483646 ...
1 11 65 399 2473 15381 95757 596341 ...
-
diff = 3; m0 = 4; mmax = 13;
TransferGf[m_, u_, t_, v_, z_] := Array[u, m].LinearSolve[IdentityMatrix[m] - z*Array[t, {m, m}], Array[v, m]]
RowGf[d_, m_, z_] := 1+z*TransferGf[m, 1&, Boole[Abs[#1-#2] <= d]&, 1&, z];
row[m_] := row[m] = CoefficientList[RowGf[diff, m, x] + O[x]^mmax, x];
T[m_ /; m >= m0, n_ /; n >= 0] := row[m][[n + 1]];
Table[T[m - n, n], {m, m0, mmax}, {n, m - m0, 0, -1}] // Flatten (* Jean-François Alcover, Jun 17 2017, adapted from PARI *)
-
TransferGf(m,u,t,v,z)=vector(m,i,u(i))*matsolve(matid(m)-z*matrix(m,m,i,j,t(i,j)),vectorv(m,i,v(i)));
RowGf(d,m,z)=1+z*TransferGf(m, i->1, (i,j)->abs(i-j)<=d, j->1, z);
for(m=4, 12, print(RowGf(3,m,x)));
for(m=4, 12, v=Vec(RowGf(3,m,x) + O(x^9)); for(n=1, length(v), print1( v[n], ", ") ); print(); );
A188860
Number of n X n binary arrays without the pattern 0 1 diagonally, vertically or antidiagonally.
Original entry on oeis.org
1, 2, 7, 26, 95, 340, 1193, 4116, 14001, 47064, 156629, 516844, 1693073, 5511218, 17841247, 57477542, 184377699, 589195584, 1876395357, 5957318820, 18861068265, 59563612974, 187668462027, 590039959434, 1851508693479, 5799494052414, 18135645594003
Offset: 0
Some solutions for 3X3
..1..1..1....0..0..0....1..1..1....1..1..1....1..1..0....1..1..1....1..1..1
..1..1..1....0..0..0....1..1..1....1..0..0....0..0..0....1..1..1....1..1..1
..1..1..0....0..0..0....1..0..0....0..0..0....0..0..0....1..0..1....0..0..0
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a:= proc(n) option remember; `if`(n<3, (2*n-1)*n+1,
((10*n^2-49*n+33)*a(n-1)-(6*n^2-9*n-33)*a(n-2)
-(9*(n-3))*(2*n-7)*a(n-3))/((n-1)*(2*n-9)))
end:
seq(a(n), n=0..35); # Alois P. Heinz, Mar 30 2017
A188865
Number of n X 8 binary arrays without the pattern 0 1 diagonally, vertically or antidiagonally.
Original entry on oeis.org
256, 1393, 3194, 5275, 7442, 9627, 11814, 14001, 16188, 18375, 20562, 22749, 24936, 27123, 29310, 31497, 33684, 35871, 38058, 40245, 42432, 44619, 46806, 48993, 51180, 53367, 55554, 57741, 59928, 62115, 64302, 66489, 68676, 70863, 73050, 75237, 77424
Offset: 1
Some solutions for 3 X 8:
..1..1..1..1..1..1..1..1....1..1..1..1..1..1..1..1....1..1..0..1..1..1..1..1
..1..1..1..1..1..1..1..1....1..1..1..1..1..1..1..1....0..0..0..0..1..1..1..1
..0..0..0..0..1..1..1..0....0..0..1..0..1..1..1..0....0..0..0..0..0..0..0..0
A188862
Number of n X 5 binary arrays without the pattern 0 1 diagonally, vertically or antidiagonally.
Original entry on oeis.org
32, 99, 178, 259, 340, 421, 502, 583, 664, 745, 826, 907, 988, 1069, 1150, 1231, 1312, 1393, 1474, 1555, 1636, 1717, 1798, 1879, 1960, 2041, 2122, 2203, 2284, 2365, 2446, 2527, 2608, 2689, 2770, 2851, 2932, 3013, 3094, 3175, 3256, 3337, 3418, 3499, 3580
Offset: 1
Some solutions for 3 X 5:
..1..1..1..1..0....1..1..1..1..1....1..1..1..1..1....1..1..1..1..1
..1..0..0..0..0....1..1..0..1..1....0..1..1..1..1....1..1..1..1..1
..0..0..0..0..0....0..0..0..0..0....0..0..1..0..1....0..1..0..1..1
A188863
Number of n X 6 binary arrays without the pattern 0 1 diagonally, vertically or antidiagonally.
Original entry on oeis.org
64, 239, 466, 707, 950, 1193, 1436, 1679, 1922, 2165, 2408, 2651, 2894, 3137, 3380, 3623, 3866, 4109, 4352, 4595, 4838, 5081, 5324, 5567, 5810, 6053, 6296, 6539, 6782, 7025, 7268, 7511, 7754, 7997, 8240, 8483, 8726, 8969, 9212, 9455, 9698, 9941, 10184
Offset: 1
Some solutions for 3 X 6:
..1..1..1..0..1..1....1..0..0..0..0..0....1..1..1..1..1..0....1..1..1..1..1..1
..0..0..0..0..0..0....0..0..0..0..0..0....1..0..1..0..0..0....0..1..1..1..1..1
..0..0..0..0..0..0....0..0..0..0..0..0....0..0..0..0..0..0....0..0..0..1..1..0
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