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A018226 Magic numbers: atoms with one of these numbers of protons or neutrons in their nuclei are considered to be stable. +0
19
2, 8, 20, 28, 50, 82, 126 (list; graph; listen)
OFFSET

1,1

COMMENT

A Google search on `"2,8,20,28,50" Magic number` will turn up hundreds of other links.

First seven positive terms of A162626, the magic sequence. [From Omar E. Pol (info(AT)polprimos.com), Jul 07 2009]

REFERENCES

A brief description is given under "Magic numbers" in the Encyclopedia Britannica.

S. Bjornholm, Clusters..., Contemp. Phys. 31 1990 pp. 309-324 (p. 312).

Dictionary of Science (Simon and Schuster), see the entry for "Magic number".

J. Fridmann et al., 'Magic' nucleus 42-Si, Nature, 435 (2005), 922-924 and 897-898.

J. Glanz, Uut and Uup Add Their Atomic Mass to Periodic Table, New York Times, Feb 01, 2003, pages 1 and 26.

R. V. F. Janssens, Unexpected doubly magic nucleus, Nature, 459 (jun 25 2009), 1069-1070. _Added by N. J. A. Sloane, Jul 05 2009]

D. Warner, Not-so-magic numbers, Nature, 430 (Jul 29 2004), 517-519.

LINKS

Radoslav Jovanovic, Magic Numbers and the Pascal Triangle

V. Ladma, Magic Numbers

NAPC Isotope Hudrology Section, Chapter 2, Atomic Systematics and Nuclear Structure

D. Weise, The Pythagorean Approach to Problems of Periodicity in Chemistry and Nuclear Physics"

FORMULA

If n is prime and nearest-neighbor of a prime then a(n)=n(n+1)(n+2)/3 else a(n)=n(n^2+5)/3, where 0<n<8. [From Omar E. Pol (info(AT)polprimos.com), Jul 07 2009]

MAPLE

Contribution from Omar E. Pol (info(AT)polprimos.com), Jul 07 2009: (Start)

For n=1 to 7

If n=2 or n=3 then a(n)=n(n+1)(n+2)/3 else a(n)=n(n^2+5)/3

next n

(End)

CROSSREFS

Cf. A018227, A033547, A110856.

Cf. A130598, A162626. [From Omar E. Pol (info(AT)polprimos.com), Jul 07 2009]

Sequence in context: A136904 A043002 A108180 this_sequence A162626 A137306 A110856

Adjacent sequences: A018223 A018224 A018225 this_sequence A018227 A018228 A018229

KEYWORD

nonn,fini,full

AUTHOR

John Raithel (raithel(AT)rahul.net)

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Last modified December 7 08:40 EST 2009. Contains 170430 sequences.


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