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 1-5 of 5 results.

A099955 Atomic numbers in first column in the Mendeleyev periodic table of elements.

Original entry on oeis.org

1, 3, 11, 19, 37, 55, 87
Offset: 1

Views

Author

Parthasarathy Nambi, Nov 12 2004

Keywords

Comments

Atomic numbers of hydrogen and then the alkali metals.

Examples

			The atomic number of sodium is 11.

Crossrefs

Cf. A099956, alkaline earth metals; A101648, metalloids; A101647, nonmetals (except halogens and noble gases); A097478, halogens; A018227, noble gases; A101649, poor metals.

Formula

a(n) = A018227(n-1) + 1. - Lekraj Beedassy, Mar 31 2006

Extensions

Edited by N. J. A. Sloane at the suggestion of Lekraj Beedassy, Jan 13 2008

A099956 Atomic numbers of the alkaline earth metals.

Original entry on oeis.org

4, 12, 20, 38, 56, 88
Offset: 1

Views

Author

Parthasarathy Nambi, Nov 12 2004

Keywords

Examples

			12 is the atomic number of magnesium.

Crossrefs

Cf. A099955, alkali metals; A101648, metalloids; A101647, nonmetals (except halogens and noble gases); A097478, halogens; A018227, noble gases; A101649, poor metals.

A101649 Atomic numbers of the poor metals on the periodic table.

Original entry on oeis.org

13, 31, 49, 50, 81, 82, 83
Offset: 1

Views

Author

Robert Happelberg (roberthappelberg(AT)yahoo.com), Dec 10 2004

Keywords

Comments

Elements 113, 114 and 115 are believed to be poor metals too. Element 116 could be either a poor metal or a metalloid. So I'm not putting the keyword full at this time. The poor metals are between the metalloids and the transition metals on the periodic table.

Examples

			The atomic number of aluminium is 13.

References

  • The New Encyclopaedia Britannica, 15th Edition, 1991, Volume 15 (Macropedia), Chemical Elements.

Links

Crossrefs

Cf. A099955, alkali metals; A099956, alkaline earth metals; A101648, metalloids; A101647, nonmetals (except halogens and noble gases); A097478, halogens; A018227, noble gases; A101649, poor metals.

A097478 Atomic numbers of halogens in the periodic table.

Original entry on oeis.org

9, 17, 35, 53, 85, 117
Offset: 1

Views

Author

Parthasarathy Nambi, Sep 19 2004

Keywords

Comments

The halogens are all on the second rightmost column of the periodic table. (The rightmost column belongs to the noble gases.) - Alonso del Arte, Apr 26 2011
Halogens: 9, fluorine (F); 17;,chlorine (Cl); 35, bromine (Br); 53, iodine (I); 85, astatine (At); and 117, tennessine (Ts). - Daniel Forgues, Jul 13 2015, Luca Khan, Sep 09 2024

References

  • Monica Halka and Brian Nordstrom, Halogens and Noble Gases, Facts On File (2010), Part 1: The Halogens.

Links

Crossrefs

Cf. A099955, alkali metals; A099956, alkaline earth metals; A101648, metalloids; A101647, nonmetals (except halogens and noble gases); A018227, noble gases; A101649, poor metals.

Formula

a(1) = 9; a(n) = a(n-1) + 2 * (ceiling(n/2) + 1)^2, 2 <= n <= 6.

A101648 Atomic numbers of the metalloids or semimetals on the periodic table.

Original entry on oeis.org

5, 14, 32, 33, 51, 52, 84
Offset: 1

Views

Author

Robert Happelberg (roberthappelberg(AT)yahoo.com), Dec 10 2004

Keywords

Comments

If ununhexium and ununseptium turn out to be metalloids, 116 and 117 should be added to this sequence, so I'm not putting the keyword full at this time. The metalloids are sandwiched between the nonmetals and the poor metals on the periodic table.

Examples

			The atomic number of boron is 5.

References

  • The New Encyclopaedia Britannica, 15th Edition, 1991, Volume 15 (Macropedia), Chemical Elements.

Links

Crossrefs

Cf. A099955, alkali metals; A099956, alkaline earth metals; A101647, nonmetals (except halogens and noble gases); A097478, halogens; A018227, noble gases; A101649, poor metals.
Showing 1-5 of 5 results.

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

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