A192409 Number of letters in the English name of the n-th element in the periodic table of the elements.

8, 6, 7, 9, 5, 6, 8, 6, 8, 4, 6, 9, 9, 7, 10, 6, 8, 5, 9, 7, 8, 8, 8, 8, 9, 4, 6, 6, 6, 4, 7, 9, 7, 8, 7, 7, 8, 9, 7, 9, 7, 10, 10, 9, 7, 9, 6, 7, 6, 3, 8, 9, 6, 5, 7, 6, 9, 6, 12, 9, 10, 8, 8, 10, 7, 10, 7, 6, 7, 9, 8, 7, 8, 8, 7, 6, 7, 8, 4, 7, 8, 4, 7, 8, 8, 5, 8, 6, 8, 7, 12, 7, 9, 9, 9, 6, 9, 11, 11, 7, 11, 8, 10, 13, 7, 10, 7, 7, 10, 12, 11, 11, 8, 9, 9, 11, 10, 9

Offset: 1

Author

Kausthub Gudipati, Jun 30 2011

Keywords

• nonn
• fini
• easy
• word

Comments

The names are based on the IUPAC Inorganic Chemistry Division table.

The sequence appears to be not very well defined, concerning the terms (names can change) and number of terms (in June/November 2016 four new names were given to elements number 113, 115, 117 and 118). - M. F. Hasler, Jan 24 2020

The names my change, certainly, but at any given time the sequence is defined by the names in the IUPAC Inorganic Chemistry Division table. - N. J. A. Sloane, Jan 25 2020

Examples

			a(1) = 8, because HYDROGEN uses 8 letters.
a(2) = 6, because HELIUM uses 6 letters.
a(3) = 7, because LITHIUM uses 7 letters.
and so on. Note that a(13) = 9, not 8, since the IUPAC spellings are used.
		

Links

• International Union of Pure and Applied Chemistry, Periodic Table of Elements
• Herbert Kaesz, The synthesis and naming of elements 110 and beyond Chemistry International 24:2 (2002), p. 7.
• W. H. Koppenol, Naming of new elements, Pure and Applied Chemistry 74:5 (2002), pp. 787-791.
• Wikipedia, Periodic table

Crossrefs

See A007656 for the atomic weights.

Cf. A005589 (letters in name of n), A070273 (letters in names of the planets), A031139 (letters in names of months), A309750 (variant: in alphabetical order).

Programs

Mathematica

Length @ Characters @ ElementData[#, "Name"] & /@ Range[118] (* Amiram Eldar, Jan 25 2020, generates all the terms in the data section with two exceptions: a(13) assumes the name "Aluminum" instead of "Aluminium" and a(55) assumes the name "Cesium" instead of "Caesium" *)

Extensions

a(7), a(32), a(35) corrected and a(51)-a(118) added by Andrew Howroyd, Jan 24 2020