

A084928


If the numbers 1 to n^3 are arranged in a cubic array, a(n) is the minimum number of primes in each row of the n^2 rows in the "eastwest view" that can have primes.


2



0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 1, 0, 0, 1, 0, 0, 1, 0, 1, 1, 1, 1
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OFFSET

1,1


COMMENTS

This is a threedimensional generalization of A083382.


REFERENCES

See A083382 for references and links to the twodimensional case.


LINKS

Table of n, a(n) for n=1..100.


EXAMPLE

For the case n=3, the numbers are arranged in a cubic array as follows:
1..2..3........10.11.12........19.20.21
4..5..6........13.14.15........22.23.24
7..8..9........16.17.18........25.26.27
The first row is (1,2,3), the second is (4,5,6), etc. Surprisingly, a(n) = 0 for all n from 3 to 66. It appears that a(n) > 0 for n > 128. This has been confirmed up to n = 1000.


MATHEMATICA

Table[minP=n; Do[s=0; Do[If[PrimeQ[n*(c1)+r], s++ ], {r, n}]; minP=Min[s, minP], {c, n^2}]; minP, {n, 100}]


CROSSREFS

Cf. A083382, A083414, A084927 (top view), A084929 (northsouth view).
Sequence in context: A159075 A178333 A063524 * A033683 A216284 A130638
Adjacent sequences: A084925 A084926 A084927 * A084929 A084930 A084931


KEYWORD

nonn


AUTHOR

T. D. Noe, Jun 12 2003


STATUS

approved



