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.

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A355048 Number of unoriented orthoplex n-ominoes with cell centers determining n-3 space.

Original entry on oeis.org

3, 18, 122, 655, 3240, 14531, 61520, 247381, 958434, 3598594, 13180348, 47274577, 166642096, 578750970, 1984671466, 6731351834, 22612409886, 75321920403, 249028297179, 817867225710, 2670093233760, 8670380548402
Offset: 6

Views

Author

Robert A. Russell, Jun 16 2022

Keywords

Comments

Orthoplex polyominoes are connected sets of cells of regular tilings with Schläfli symbols {}, {4}, {3,4}, {3,3,4}, {3,3,3,4}, etc. These are tilings of regular orthoplexes projected on their circumspheres. Orthoplex polyominoes are equivalent to multidimensional polyominoes that do not extend more than two units along any axis, i.e., fit within a 2^d cube. For unoriented polyominoes, chiral pairs are counted as one.

Examples

			a(6)=3 because there are 3 hexominoes in 2^3 space. The two vacant cells share just a face, an edge, or a vertex.

Links

Crossrefs

Cf. A355047 (oriented), A355049 (chiral), A355050 (achiral) A355051 (asymmetric), A000081 (rooted trees).
Other dimensions: A036367 (n-2), A000055 (n-1), A355053 (multidimensional).

Programs

  • Mathematica
    sb[n_,k_] := sb[n,k] = b[n+1-k,1] + If[n<2k,0,sb[n-k,k]];
b[1,1] := 1; b[n_,1] := b[n,1] = Sum[b[i,1]sb[n-1,i]i,{i,1,n-1}]/(n-1);
b[n_,k_] := b[n,k] = Sum[b[i,1]b[n-i,k-1],{i,1,n-1}];
nmax = 30; B[x_] := Sum[b[i,1]x^i,{i,0,nmax}]
Drop[CoefficientList[Series[(14B[x]^6 + 3B[x]^7 + 6B[x]^4B[x^2] + 6B[x]^5B[x^2] + 18B[x]^2B[x^2]^2 + 3B[x]^3B[x^2]^2 + 26B[x^2]^3 + 6 B[x]B[x^2](B[x^2]^2 + B[x^4]) + 4B[x^3]^2 + 4B[x^6]) / 24 + B[x]^3 (38B[x]^4 + 9B[x]^5 + 4B[x]^2B[x^2] + 10B[x]^3B[x^2] + 2B[x^2]^2 + B[x]B[x^2]^2) / (8(1-B[x])) + B[x]^6 (16B[x]^2 + 6B[x]^3 + B[x^2] + B[x] (5 + 2B[x^2])) / (2(1-B[x])^2) + B[x]^7 (2 + 42B[x] + 51B[x]^2 + 24B[x]^3 + 3B[x^2]) / (12(1-B[x])^3) + B[x]^9 (17 + 8B[x]) / (8(1-B[x])^4) + 3B[x]^10 / (8(1-B[x])^5) + B[x^2]^2(B[x]^4 + 4B[x]^2 B[x^2] + 12B[x^2]^2 + B[x^4] + B[x] (8B[x^2] + 5B[x^2]^2 + B[x^4])) / (4(1-B[x^2])) + B[x^2]^4 (8 + 16B[x^2] + B[x] (19 + 8B[x^2])) / (8(1-B[x^2])^2) + 3(1 + B[x])B[x^2]^5 / (4(1-B[x^2])^3) + 2B[x]B[x^3]^2 / (6(1-B[x^3])) + B[x]B[x^4]^2 / (4(1-B[x^4])) + B[x]^2B[x^2]^2(5B[x]^3 + 2B[x^2] + B[x](2 + B[x^2])) / (4(1-B[x])(1-B[x^2])) + B[x]^5(1+4B[x])B[x^2]^2 / (4(1-B[x])^2(1-B[x^2])) + B[x]^6 B[x^2]^2 / (4(1-B[x])^3(1-B[x^2])) + 3B[x]^2B[x^2]^4 / (8(1-B[x])(1-B[x^2])^2) + B[x^2](1+B[x])B[x^4]^2 / (4(1-B[x^2])(1-B[x^4])), {x,0,nmax}],x],6]

Formula

a(n) = A355047(n) - A355049(n) = (A355047(n) + A355050(n)) / 2 = A355049(n) + A355050(n).
G.f.: (14*B(x)^6 + 3*B(x)^7 + 6*B(x)^4*B(x^2) + 6*B(x)^5*B(x^2) + 18*B(x)^2*B(x^2)^2 + 3*B(x)^3*B(x^2)^2 + 26*B(x^2)^3 + 6*B(x)*B(x^2)*(B(x^2)^2 + B(x^4)) + 4*B(x^3)^2 + 4*B(x^6)) / 24 + B(x)^3*(38*B(x)^4 + 9*B(x)^5 + 4*B(x)^2*B(x^2) + 10*B(x)^3*B(x^2) + 2*B(x^2)^2 + B(x)*B(x^2)^2) / (8*(1-B(x))) + B(x)^6*(16*B(x)^2 + 6*B(x)^3 + B(x^2) + B(x)*(5 + 2*B(x^2))) / (2*(1-B(x))^2) + B(x)^7*(2 + 42*B(x) + 51*B(x)^2 + 24*B(x)^3 + 3*B(x^2)) / (12*(1-B(x))^3) + B(x)^9*(17 + 8*B(x)) / (8*(1-B(x))^4) + 3*B(x)^10 / (8*(1-B(x))^5) + B(x^2)^2*(B(x)^4 + 4*B(x)^2*B(x^2) + 12*B(x^2)^2 + B(x^4) + B(x)*(8*B(x^2) + 5*B(x^2)^2 + B(x^4))) / (4*(1-B(x^2))) + B(x^2)^4*(8 + 16*B(x^2) + B(x)*(19 + 8*B(x^2))) / (8*(1-B(x^2))^2) + 3*(1 + B(x))*B(x^2)^5 / (4*(1-B(x^2))^3) + 2*B(x)*B(x^3)^2 / (6*(1-B(x^3))) + B(x)*B(x^4)^2 / (4*(1-B(x^4))) + B(x)^2*B(x^2)^2*(5*B(x)^3 + 2*B(x^2) + B(x)*(2 + B(x^2))) / (4*(1-B(x))*(1-B(x^2))) + B(x)^5*(1+4*B(x))*B(x^2)^2 / (4*(1-B(x))^2*(1-B(x^2))) + B(x)^6*B(x^2)^2 / (4*(1-B(x))^3*(1-B(x^2))) + 3*B(x)^2*B(x^2)^4 / (8*(1-B(x))*(1-B(x^2))^2) + B(x^2)*(1+B(x))*B(x^4)^2 / (4*(1-B(x^2))*(1-B(x^4))), where B(x) is the generating function for rooted trees with n nodes in A000081.

A355049 Number of chiral pairs of orthoplex n-ominoes with cell centers determining n-3 space.

Original entry on oeis.org

8, 76, 440, 2019, 8147, 30367, 107061, 361655, 1181761, 3762817, 11733393, 35957132, 108591703, 323914688, 955984083, 2795513143, 8108894051, 23354358683, 66838785954, 190211189706, 538567451991, 1517943035326
Offset: 7

Views

Author

Robert A. Russell, Jun 16 2022

Keywords

Comments

Orthoplex polyominoes are connected sets of cells of regular tilings with Schläfli symbols {}, {4}, {3,4}, {3,3,4}, {3,3,3,4}, etc. These are tilings of regular orthoplexes projected on their circumspheres. Orthoplex polyominoes are equivalent to multidimensional polyominoes that do not extend more than two units along any axis, i.e., fit within a 2^d cube. Each member of a chiral pair is a reflection but not a rotation of the other.

Examples

			a(7)=8 because there are 8 pairs of chiral heptominoes in 2^4 space. See trunks 1, 6, 8, 12, 13, 19, 27, and 28 in the linked Trunk Generating Functions.

Links

Crossrefs

Cf. A355047 (oriented), A355048 (unoriented), A355050 (achiral) A355051 (asymmetric), A045648 (rooted chiral).
Other dimensions: A036368 (n-2), A045649 (n-1), A355054 (multidimensional).

Programs

  • Mathematica
    sc[n_,k_] := sc[n,k] = c[n+1-k,1] + If[n<2k, 0, sc[n-k,k](-1)^k];
c[1,1] := 1; c[n_,1] := c[n,1] = Sum[c[i,1] sc[n-1,i]i, {i,1,n-1}]/(n-1);
c[n_,k_] := c[n, k] = Sum[c[i, 1] c[n-i, k-1], {i,1,n-1}];
nmax = 30; K[x_] := Sum[c[i,1] x^i, {i,0,nmax}]
Drop[CoefficientList[Series[(14 K[x]^6 + 3 K[x]^7 + 6 K[x]^4 K[-x^2] + 6 K[x]^5 K[-x^2] - 18 K[x]^2 K[-x^2]^2 + 3 K[x]^3 K[-x^2]^2 - 10 K[-x^2]^3 - 6 K[x] K[-x^2]^3 + 4 K[x^3]^2 - 6 K[x] K[-x^2] K[-x^4] + 4 K[-x^6]) / 24 + K[x]^3 (38 K[x]^4 + 9 K[x]^5 + 4 K[x]^2 K[-x^2] + 10 K[x]^3 K[-x^2] - 2 K[-x^2]^2 + K[x] K[-x^2]^2) / (8(1-K[x])) + K[x]^6 (5 K[x] + 16 K[x]^2 + 6 K[x]^3 + K[-x^2] + 2 K[x] K[-x^2]) / (2(1-K[x])^2) - K[-x^2]^2 (K[x]^4 + 2 K[x] K[-x^2] + 4 K[x]^2 K[-x^2] + 2 K[-x^2]^2 + 5 K[x] K[-x^2]^2 + K[-x^4] + K[x] K[-x^4]) / (4(1-K[-x^2])) + K[x]^7 (2 + 42 K[x] + 51 K[x]^2 + 24 K[x]^3 + 3 K[-x^2]) / (12(1-K[x])^3) + (K[x] K[x^3]^2) / (3(1-K[x^3])) - K[x]^2 K[-x^2]^2 (2 K[x] + 5 K[x]^3 + 2 K[-x^2] + K[x] K[-x^2]) / (4(1-K[x]) (1-K[-x^2])) - K[-x^2]^4 (8 + K[x] + 8 K[x] K[-x^2]) / (8(1-K[-x^2])^2) + K[x]^9 (17 + 8 K[x]) / (8(1-K[x])^4) - K[x]^5 (1 + 4 K[x]) K[-x^2]^2 / (4(1-K[x])^2 (1-K[-x^2])) + (K[x] K[-x^4]^2) / (4(1-K[-x^4])) + (3 K[x]^10) / (8(1-K[x])^5) - ((K[x]^6 K[-x^2]^2) / (4(1-K[x])^3 (1-K[-x^2]))) - (((1 + K[x]) K[-x^2]^5) / (4(1-K[-x^2])^3)) + ((1 + K[x]) K[-x^2] K[-x^4]^2) / (4(1-K[-x^2]) (1-K[-x^4])) - ((K[x]^2 K[-x^2]^4) / (8(1-K[x]) (1-K[-x^2])^2)), {x,0,nmax}], x], 7]

Formula

a(n) = A355047(n) - A355048(n) = (A355047(n) - A355050(n)) / 2 = A355048(n) - A355050(n).
G.f.: (14 C(x)^6 + 3 C(x)^7 + 6 C(x)^4 C(-x^2) + 6 C(x)^5 C(-x^2) - 18 C(x)^2 C(-x^2)^2 + 3 C(x)^3 C(-x^2)^2 - 10 C(-x^2)^3 - 6 C(x) C(-x^2)^3 + 4 C(x^3)^2 - 6 C(x) C(-x^2) C(-x^4) + 4 C(-x^6)) / 24 + C(x)^3 (38 C(x)^4 + 9 C(x)^5 + 4 C(x)^2 C(-x^2) + 10 C(x)^3 C(-x^2) - 2 C(-x^2)^2 + C(x) C(-x^2)^2) / (8(1-C(x))) + C(x)^6 (5 C(x) + 16 C(x)^2 + 6 C(x)^3 + C(-x^2) + 2 C(x) C(-x^2)) / (2(1-C(x))^2) - C(-x^2)^2 (C(x)^4 + 2 C(x) C(-x^2) + 4 C(x)^2 C(-x^2) + 2 C(-x^2)^2 + 5 C(x) C(-x^2)^2 + C(-x^4) + C(x) C(-x^4)) / (4(1-C(-x^2))) + C(x)^7 (2 + 42 C(x) + 51 C(x)^2 + 24 C(x)^3 + 3 C(-x^2)) / (12(1-C(x))^3) + (C(x) C(x^3)^2) / (3(1-C(x^3))) - C(x)^2 C(-x^2)^2 (2 C(x) + 5 C(x)^3 + 2 C(-x^2) + C(x) C(-x^2)) / (4(1-C(x)) (1-C(-x^2))) - C(-x^2)^4 (8 + C(x) + 8 C(x) C(-x^2)) / (8(1-C(-x^2))^2) + C(x)^9 (17 + 8 C(x)) / (8(1-C(x))^4) - C(x)^5 (1 + 4 C(x)) C(-x^2)^2 / (4(1-C(x))^2 (1-C(-x^2))) + (C(x) C(-x^4)^2) / (4(1-C(-x^4))) + (3 C(x)^10) / (8(1-C(x))^5) - ((C(x)^6 C(-x^2)^2) / (4(1-C(x))^3 (1-C(-x^2)))) - (((1 + C(x)) C(-x^2)^5) / (4(1-C(-x^2))^3)) + ((1 + C(x)) C(-x^2) C(-x^4)^2) / (4(1-C(-x^2)) (1-C(-x^4))) - ((C(x)^2 C(-x^2)^4) / (8(1-C(x)) (1-C(-x^2))^2)) where C(x) is the generating function for chiral n-ominoes in n-1 space, one cell labeled in A045648.

A355056 Number of asymmetric multidimensional n-ominoes with cell centers determining n-3 space.

Original entry on oeis.org

5, 46, 275, 1283, 5281, 19607, 68476, 227196, 727780, 2263148, 6881482, 20529511, 60312548, 174870492, 501443277, 1424142358, 4011274417, 11216074419, 31160837273, 86078096135, 236568911194, 647181951619
Offset: 5

Views

Author

Robert A. Russell, Jun 16 2022

Keywords

Comments

Multidimensional polyominoes are connected sets of cells of regular tilings with Schläfli symbols {oo}, {4,4}, {4,3,4}, {4,3,3,4}, etc. Each tile is a regular orthotope (hypercube). An asymmetric polyomino has a symmetry group of order 1.

Examples

			a(5)=5 as there are exactly five asymmetric pentominoes in 2-space.

Links

Crossrefs

Cf. A355052 (oriented), A355053 (unoriented), A355054 (chiral), A355055 (achiral), A191092 (fixed), A004111 (rooted asymmetric).
Other dimensions: A036366 (n-2), A000220 (n-1), A355051 (orthoplex).

Programs

  • Mathematica
    sa[n_, k_] := sa[n, k] = a[n+1-k, 1] + If[n < 2 k, 0, -sa[n-k, k]];
a[1, 1] := 1; a[n_, 1] := a[n, 1] = Sum[a[i, 1] sa[n-1, i] i, {i, 1, n-1}]/(n-1);
a[n_, k_] := a[n, k] = Sum[a[i, 1] a[n-i, k-1], {i, 1, n-1}];
nmax = 30; A[x_] := Sum[a[i, 1] x^i, {i, 0, nmax}]
Drop[CoefficientList[Series[(4 A[x]^4 + 37 A[x]^5 + 12 A[x]^6 - 6 A[x]^3 A[x^2] - 10 A[x]^4 A[x^2] - 4 A[x^2]^2 - 17 A[x] A[x^2]^2 - 2 A[x^2]^3 + 2 A[x] A[x^4]) / 8 + (24 A[x]^5 + 515 A[x]^6 + 325 A[x]^7 + 24 A[x]^8 - 48 A[x]^4 A[x^2] - 96 A[x]^5 A[x^2] - 24 A[x]^6 A[x^2] - 21 A[x]^2 A[x^2]^2 + 21 A[x]^3 A[x^2]^2 - 14 A[x^2]^3 + 8 A[x] A[x^2]^3 + 6 A[x]^2 A[x^2]^3 + 4 A[x^3]^2 - 4 A[x] A[x^3]^2 + 24 A[x^2] A[x^4] - 18 A[x] A[x^2] A[x^4] - 6 A[x]^2 A[x^2] A[x^4] - 4 A[x^6] + 4 A[x] A[x^6]) / (24 (1-A[x])) + A[x]^5 (2 A[x] + 67 A[x]^2 + 46 A[x]^3 + 6 A[x]^4 - 3 A[x^2] - 6 A[x] A[x^2] - 2 A[x]^2 A[x^2]) / (2 (1-A[x])^2) - A[x^2] (2 A[x]^2 A[x^2] + 6 A[x]^3 A[x^2] + 2 A[x]^4 A[x^2] + 13 A[x^2]^2 + 31 A[x] A[x^2]^2 + 2 A[x]^2 A[x^2]^2 + 15 A[x^2]^3 + 5 A[x] A[x^2]^3 - 3 A[x^4] - 5 A[x] A[x^4] - 3 A[x^2] A[x^4] - A[x] A[x^2] A[x^4]) / (4 (1-A[x^2])) + A[x]^6 (4 A[x] + 153 A[x]^2 + 75 A[x]^3 + 12 A[x]^4 - 3 A[x^2] - 3 A[x] A[x^2]) / (6 (1-A[x])^3) - A[x]^2 A[x^2]^2 (2 A[x] + 7 A[x]^2 + 5 A[x]^3 + A[x^2] - A[x] A[x^2]) / (2 (1-A[x]) (1-A[x^2])) + A[x] A[x^3]^2 / (1-A[x^3]) / 3 + A[x]^9 (21 + 4 A[x]) / (2 (1-A[x])^4) - A[x]^5 (3 + 2 A[x]) A[x^2]^2 / ((1-A[x])^2 (1-A[x^2])) - A[x^2]^4 (5 + 7 A[x] + 3 A[x^2] + A[x] A[x^2]) / (1-A[x^2])^2 + A[x] A[x^4]^2 / (2 (1-A[x^4])) + 3 A[x]^10 / (2 (1-A[x])^5) - A[x]^6 A[x^2]^2 / ((1-A[x])^3 (1-A[x^2])) - 2 (1 + A[x]) A[x^2]^5 / (1-A[x^2])^3 + 3 (1 + A[x]) A[x^2] A[x^4]^2 / (2 (1-A[x^2]) (1-A[x^4])), {x,0,nmax}], x], 5]

Formula

G.f.: (4 A(x)^4 + 37 A(x)^5 + 12 A(x)^6 - 6 A(x)^3 A(x^2) - 10 A(x)^4 A(x^2) - 4 A(x^2)^2 - 17 A(x) A(x^2)^2 - 2 A(x^2)^3 + 2 A(x) A(x^4)) / 8 + (24 A(x)^5 + 515 A(x)^6 + 325 A(x)^7 + 24 A(x)^8 - 48 A(x)^4 A(x^2) - 96 A(x)^5 A(x^2) - 24 A(x)^6 A(x^2) - 21 A(x)^2 A(x^2)^2 + 21 A(x)^3 A(x^2)^2 - 14 A(x^2)^3 + 8 A(x) A(x^2)^3 + 6 A(x)^2 A(x^2)^3 + 4 A(x^3)^2 - 4 A(x) A(x^3)^2 + 24 A(x^2) A(x^4) - 18 A(x) A(x^2) A(x^4) - 6 A(x)^2 A(x^2) A(x^4) - 4 A(x^6) + 4 A(x) A(x^6)) / (24 (1-A(x))) + A(x)^5 (2 A(x) + 67 A(x)^2 + 46 A(x)^3 + 6 A(x)^4 - 3 A(x^2) - 6 A(x) A(x^2) - 2 A(x)^2 A(x^2)) / (2 (1-A(x))^2) - A(x^2) (2 A(x)^2 A(x^2) + 6 A(x)^3 A(x^2) + 2 A(x)^4 A(x^2) + 13 A(x^2)^2 + 31 A(x) A(x^2)^2 + 2 A(x)^2 A(x^2)^2 + 15 A(x^2)^3 + 5 A(x) A(x^2)^3 - 3 A(x^4) - 5 A(x) A(x^4) - 3 A(x^2) A(x^4) - A(x) A(x^2) A(x^4)) / (4 (1-A(x^2))) + A(x)^6 (4 A(x) + 153 A(x)^2 + 75 A(x)^3 + 12 A(x)^4 - 3 A(x^2) - 3 A(x) A(x^2)) / (6 (1-A(x))^3) - A(x)^2 A(x^2)^2 (2 A(x) + 7 A(x)^2 + 5 A(x)^3 + A(x^2) - A(x) A(x^2)) / (2 (1-A(x)) (1-A(x^2))) + A(x) A(x^3)^2 / (1-A(x^3)) / 3 + A(x)^9 (21 + 4 A(x)) / (2 (1-A(x))^4) - A(x)^5 (3 + 2 A(x)) A(x^2)^2 / ((1-A(x))^2 (1-A(x^2))) - A(x^2)^4 (5 + 7 A(x) + 3 A(x^2) + A(x) A(x^2)) / (1-A(x^2))^2 + A(x) A(x^4)^2 / (2 (1-A(x^4))) + 3 A(x)^10 / (2 (1-A(x))^5) - A(x)^6 A(x^2)^2 / ((1-A(x))^3 (1-A(x^2))) - 2 (1 + A(x)) A(x^2)^5 / (1-A(x^2))^3 + 3 (1 + A(x)) A(x^2) A(x^4)^2 / (2 (1-A(x^2)) (1-A(x^4))) where A(x) is the generating function for rooted identity trees with n nodes in A004111.

A355047 Number of oriented orthoplex n-ominoes with cell centers determining n-3 space.

Original entry on oeis.org

3, 26, 198, 1095, 5259, 22678, 91887, 354442, 1320089, 4780355, 16943165, 59007970, 202599228, 687342673, 2308586154, 7687335917, 25407923029, 83430814454, 272382655862, 884706011664, 2860304423466, 9208948000393
Offset: 6

Views

Author

Robert A. Russell, Jun 16 2022

Keywords

Comments

Orthoplex polyominoes are connected sets of cells of regular tilings with Schläfli symbols {}, {4}, {3,4}, {3,3,4}, {3,3,3,4}, etc. These are tilings of regular orthoplexes projected on their circumspheres. Orthoplex polyominoes are equivalent to multidimensional polyominoes that do not extend more than two units along any axis, i.e., fit within a 2^d cube. This sequence is obtained using the first formula below. For oriented polyominoes, chiral pairs are counted as two.

Examples

			a(6)=3 because there are 3 hexominoes in 2^3 space, all achiral. The two vacant cells share just a face, an edge, or a vertex.

Crossrefs

Cf. A355048 (unoriented), A355049 (chiral), A355050 (achiral) A355051 (asymmetric), A355052 (multidimensional).

Formula

a(n) = A355048(n) + A355049(n) = 2*A355048(n) - A355050(n) = 2*A355049(n) + A355050(n).

A355050 Number of achiral orthoplex n-ominoes with cell centers determining n-3 space.

Original entry on oeis.org

3, 10, 46, 215, 1221, 6384, 31153, 140320, 596779, 2416833, 9417531, 35541184, 130684964, 470159267, 1660756778, 5775367751, 19816896743, 67213026352, 225673938496, 751028439756, 2479882044054, 8131813096411
Offset: 6

Views

Author

Robert A. Russell, Jun 16 2022

Keywords

Comments

Orthoplex polyominoes are connected sets of cells of regular tilings with Schläfli symbols {}, {4}, {3,4}, {3,3,4}, {3,3,3,4}, etc. These are tilings of regular orthoplexes projected on their circumspheres. Orthoplex polyominoes are equivalent to multidimensional polyominoes that do not extend more than two units along any axis, i.e., fit within a 2^d cube. This sequence is obtained using the first formula below. An achiral polyomino is identical to its reflection.

Examples

			a(6)=3 because there are 3 hexominoes in 2^3 space, all achiral. The two vacant cells share just a face, an edge, or a vertex.

Crossrefs

Cf. A355047 (oriented), A355048 (unoriented), A355049 (chiral), A355051 (asymmetric), A355055 (multidimensional).

Formula

a(n) = A355048(n) - A355049(n) = 2*A355048(n) - A355047(n) = A355047(n) - 2*A355049(n).

A355999 Number of fixed orthoplex n-ominoes with cell centers determining (n-3)-space.

Original entry on oeis.org

28, 4240, 344320, 23872320, 1603840000, 109616815616, 7785535242240, 580217967114240, 45559682696478700, 3774254616000000000, 329816052160897000000, 30372942170151000000000, 2943608844201080000000000
Offset: 6

Views

Author

Robert A. Russell, Jul 22 2022

Keywords

Comments

Orthoplex polyominoes are connected sets of cells of regular tilings with Schläfli symbols {}, {4}, {3,4}, {3,3,4}, {3,3,3,4}, etc. These are tilings of regular orthoplexes projected on their circumspheres. Orthoplex polyominoes are equivalent to multidimensional polyominoes that do not extend more than two units along any axis, i.e., fit within a 2^d cube. Two fixed polyominoes are identical only if one is a translation of the other.

Examples

			For a(6)=28, 6 of the 8 cubes in the 2^3 space are used. There are 12 cases where the 2 empty cubes share a face, 12 cases where they share an edge, and 4 cases where they share a vertex.

Crossrefs

Cf. A191092 (multidimensional), A355048 (unoriented), A355049 (chiral), A355051 (asymmetric).
Diagonal 3 of A355997.

Programs

  • Mathematica
    Table[2^(n-6) n^(n-7) (n-3) (n-4) (n-5) (3n^3-17n^2+21n-78), {n,6,30}]
  • Python
    def A355999(n): return int(((1<Chai Wah Wu, Jul 26 2022

Formula

a(n) = 2^(n-6) * n^(n-7) * (n-3) * (n-4) * (n-5) * (3n^3-17n^2+21n-78) / 3.
a(n) ~ A191092(n) / 4.
Showing 1-6 of 6 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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