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.

A138727 Numbers n whose hexadecimal representation is the n-th member of the alphanumeric sequence: 1A, 2A, 3B, 4B, 5B, 6B, 7B, 8B, 8B, 8B, 1B, 2B, 3A, 4A, 5A, 6A, 7A, 8A. (A notation convention of the groups in the periodic table of the elements with 18 columns).

Original entry on oeis.org

26, 42, 59, 75, 91, 107, 123, 139, 139, 139, 27, 43, 58, 74, 90, 106, 122, 138
Offset: 1

Views

Author

Omar E. Pol, Apr 16 2008

Keywords

Comments

See the periodic table of the elements with 18 columns in A138723 and A138724. See A138718 for more information.

Crossrefs

Cf. A138718, A138723, A138724.

A138228 Atomic numbers at the top of the 18 groups of the Mendeleyev-Seaborg table A138724.

Original entry on oeis.org

1, 4, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 5, 6, 7, 8, 9, 2
Offset: 0

Views

Author

Paul Curtz, May 05 2008

Keywords

Comments

This refers to the following 18 elements at the top of their groups: H, Be, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, B, C, N, O, F, He.

Crossrefs

Cf. A138718, A135559.

A303149 Group number of n-th element in the periodic table, or 0 if the element does not have a group number.

Original entry on oeis.org

1, 18, 1, 2, 13, 14, 15, 16, 17, 18, 1, 2, 13, 14, 15, 16, 17, 18, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 1, 2, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 5, 6, 7, 8, 9
Offset: 1

Views

Author

Felix Fröhlich, Apr 22 2018

Keywords

Comments

a(n) is 0 for the f-block elements.

Links

Crossrefs

Cf. A138718.
Showing 1-3 of 3 results.

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