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 1-3 of 3 results.

A255537 Number of connected pointed-irreducible digital images of n points up to homotopy equivalence.

Original entry on oeis.org

1, 0, 0, 0, 1, 2, 9, 68, 1110
Offset: 1

Views

Author

P. Christopher Staecker, Feb 24 2015

Keywords

Comments

"Pointed-irreducible" means that the identity map is not homotopic to any nonsurjective map having a fixed point.

Links

Crossrefs

Cf. A248571.

A255538 Number of connected rigid digital images of n points, up to isomorphism.

Original entry on oeis.org

1, 0, 0, 0, 0, 0, 2, 26, 544
Offset: 1

Views

Author

P. Christopher Staecker, Feb 24 2015

Keywords

Comments

Rigid means that the identity map is not homotopic to any other map.

Links

Crossrefs

Cf. A248571, A255537.

A306725 Number of connected strong irreducible digital images of n points up to strong homotopy equivalence.

Original entry on oeis.org

1, 0, 0, 1, 2, 9, 46, 507, 11800
Offset: 1

Views

Author

P. Christopher Staecker, Mar 06 2019

Keywords

Comments

"Strong irreducible" means not strong homotopy equivalent to an image of fewer points. Each term is greater than or equal to the corresponding term of A248571.

Links

Crossrefs

Cf. A248571.
Showing 1-3 of 3 results.

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

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