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A111128 Scores for Part 2 of the n X n generalization of the Gordon Lee puzzle. 1
2, 21, 72, 181, 390, 715 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

See A109943 and the references therein for more information.

1192 and 1847 are lower bounds for the next terms a(7) and a(8).

LINKS

Table of n, a(n) for n=1..6.

Eric Weisstein's World of Mathematics, Prime Array.

Al Zimmermann's Programming Contests. Primal Squares: The Problem

Al Zimmermann's Programming Contests. Primal Squares: Best grids for part 1 found during the contest.

Al Zimmermann's Programming Contests. Primal Squares: Part 2 solutions

EXAMPLE

a(2)=21 is the "part 2" score for the matrix

  4 7

  3 1

which contains two single-digit primes and one even number (score: 2+1)

and 9 2-digit primes: 13,17,31,37,41,43,47,71,73 score(9*2); total = 3+18 = 21.

CROSSREFS

Cf. A032529 = all primes in the 3 X 3 record matrix, A034720 = number of candidates to be checked for primality in an n X n matrix of single digits.

Sequence in context: A075681 A212257 A034520 * A213827 A129556 A077209

Adjacent sequences:  A111125 A111126 A111127 * A111129 A111130 A111131

KEYWORD

hard,more,nonn

AUTHOR

Hugo Pfoertner, Sep 21 2005

STATUS

approved

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Last modified August 7 09:16 EDT 2020. Contains 336274 sequences. (Running on oeis4.)