A094458 Initial members of 25 consecutive primes in a 5 X 5 spiral wherein the mean of all 12 sums is prime.

3, 71, 433, 587, 751, 1249, 2213, 2531, 2621, 4177, 4211, 4783, 5749, 5903, 6197, 6569, 6719, 7213, 8101, 8513, 8669, 9091, 10091, 10093, 10151, 10723, 10771, 12373, 12503, 13003, 16217, 17359, 18493, 19429, 20287, 20441, 20479, 22051, 22637

Offset

1,1

Links

Table of n, a(n) for n=1..39.

Formula

Arrange 25 consecutive primes in a 5 X 5 grid wherein YJKLM, XIBCN, WHADO, VGFEP, UTSRQ are the first through 5th horizontal rows of primes. Then sum the rows horizontally, vertically and along the two main diagonals. Total the 12 sums, divide by 12 and if the mean is integral and prime, adjoin initial prime to the sequence.

Example

a(1)=3 because 3 is the first of 25 primes arranged in a 5 X 5 grid wherein the mean of all 12 sums is 223, prime.

Crossrefs

Cf. A094459 A094454.

Sequence in context: A254665 A106894 A166449 * A183548 A111649 A349072

Adjacent sequences: A094455 A094456 A094457 * A094459 A094460 A094461

Keyword

easy,nonn

Author

Enoch Haga, May 06 2004

Status

approved