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A014085 Number of primes between n^2 and (n+1)^2. +0
30
0, 2, 2, 2, 3, 2, 4, 3, 4, 3, 5, 4, 5, 5, 4, 6, 7, 5, 6, 6, 7, 7, 7, 6, 9, 8, 7, 8, 9, 8, 8, 10, 9, 10, 9, 10, 9, 9, 12, 11, 12, 11, 9, 12, 11, 13, 10, 13, 15, 10, 11, 15, 16, 12, 13, 11, 12, 17, 13, 16, 16, 13, 17, 15, 14, 16, 15, 15, 17, 13, 21, 15, 15, 17, 17, 18, 22, 14, 18, 23, 13 (list; graph; listen)
OFFSET

0,2

COMMENT

Suggested by Legendre's conjecture (still open) that there is always a prime between n^2 and (n+1)^2.

REFERENCES

J. R. Goldman, The Queen of Mathematics, 1998, p. 82.

LINKS

T. D. Noe, Table of n, a(n) for n = 0..10000

Eric Weisstein's World of Mathematics, Legendre's Conjecture

M. Hassani, Counting primes in the interval (n^2, (n+1)^2)

FORMULA

a(n) is the number of occurrences of n in A000006 . - DELEHAM Philippe (kolotoko(AT)wanadoo.fr), Dec 17 2003

EXAMPLE

a(17)=5 because between 17^2 and 18^2, i.e. 289 and 324 there are 5 primes (which are 293, 307, 311, 313, 317).

MATHEMATICA

Table[ct = PrimePi[(k + 1)^2] - PrimePi[k^2], {k, 0, 80}]. - Lei Zhou (lzhou5@emory.edu), Dec 01 2005

CROSSREFS

Cf. A053000, A053001, A007491.

Cf. A077766, A077767.

Cf. A000006.

Sequence in context: A126336 A134446 A125749 this_sequence A029210 A035433 A029199

Adjacent sequences: A014082 A014083 A014084 this_sequence A014086 A014087 A014088

KEYWORD

nonn,easy,nice

AUTHOR

Jonathan Wild (jon(AT)sound.music.mcgill.ca)

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Last modified July 25 07:41 EDT 2008. Contains 142293 sequences.


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