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.

Previous Showing 21-23 of 23 results.

A173878 Number of six-dimensional simplical toric diagrams with hypervolume n.

Original entry on oeis.org

1, 3, 7, 23, 19, 65, 46, 202, 156, 281, 183, 972, 333, 903, 1029, 2507, 912
Offset: 1

Views

Author

Rak-Kyeong Seong (rak-kyeong.seong(AT)imperial.ac.uk), Mar 01 2010

Keywords

Comments

Also gives the number of distinct abelian orbifolds of C^7/Gamma, Gamma in SU(7).

Crossrefs

Cf. A003051 (No. of two-dimensional triangular toric diagrams of area n), A045790 (No. of three-dimensional tetrahedral toric diagrams of volume n), A173824 (No. of four-dimensional simplical toric diagrams of hypervolume n), A173877 (No. of five-dimensional simplical toric diagrams of hypervolume n).

Extensions

a(8)-a(16) from Balletti's data and a(17) from Table 15 of Hanany & Seong 2011 added by Andrey Zabolotskiy, Mar 13 2020

A300784 Number of symmetrically distinct sublattices (supercells, superlattices, HNFs) of the tetragonal lattice of index n.

Original entry on oeis.org

1, 5, 5, 17, 9, 29, 13, 51, 28, 53, 25, 115, 33, 81, 73, 153, 51, 176, 61, 219, 121, 161, 85, 403, 126, 213, 188, 353, 129, 473, 145, 487, 257, 335, 261, 776, 201, 405, 345, 815, 243, 801, 265, 731, 584, 569, 313, 1407, 398, 838, 559, 975, 393, 1256, 573, 1375
Offset: 1

Views

Author

Andrey Zabolotskiy, Mar 12 2018

Keywords

Crossrefs

Programs

  • Python
    # see A159842 for the definition of dc, fin, per, u, N, N2
    def a(n):
        return (dc(u, N, N2)(n) + 2*dc(fin(1, -1, 0, 4), u, u, N)(n)
          + 3*dc(fin(1, 3), u, u, N)(n)
          + 2*dc(fin(1, 1), u, u, per(0, 1, 0, -1))(n)) // 8
    print([a(n) for n in range(1, 300)])
    # Andrey Zabolotskiy, Jan 31 2020

Extensions

Terms a(11) and beyond from Andrey Zabolotskiy, Jan 31 2020

A157235 Number of primitive inequivalent oblique sublattices of hexagonal (triangular) lattice of index n (equivalence and symmetry of sublattices are determined using only parent lattice symmetries).

Original entry on oeis.org

0, 0, 0, 0, 0, 1, 0, 0, 1, 2, 1, 2, 1, 3, 2, 2, 2, 5, 2, 4, 3, 5, 3, 4, 4, 6, 5, 6, 4, 10, 4, 6, 6, 8, 6, 10, 5, 9, 7, 8, 6, 14, 6, 10, 10, 11, 7, 12, 8, 14, 10, 12, 8, 17, 10, 12, 11, 14, 9, 20, 9, 15, 14, 14, 12, 22, 10, 16, 14, 22, 11, 20, 11, 18, 18, 18
Offset: 1

Views

Author

N. J. A. Sloane, Feb 25 2009

Keywords

Crossrefs

Cf. A003051 (all sublattices), A003050 (all primitive sublattices), A154272 (primitive sublattices fully inheriting the parent lattice symmetry, inlcuding the orientation of the mirrors), A000086 (primitive rotation-symmetric sublattices, counting mirror images as distinct), A060594 (primitive mirror-symmetric sublattices), A145377 (all sublattices inheriting the parent lattice symmetry), A304182.

Formula

a(n) = A003050(n) - (A000086(n)-A154272(n))/2 - A060594(n). - Andrey Zabolotskiy, Mar 19 2021

Extensions

New name and a(1)=0 prepended by Andrey Zabolotskiy, May 09 2018
Terms a(31) and beyond from Andrey Zabolotskiy, Mar 19 2021
Previous Showing 21-23 of 23 results.