

A127256


a(n)=A(n,1), the first element of each sequence A(n) defined recursively as follows. Recall that A119751 is the sequence defined recursively by a(1)=1 and a(k) is the first odd number greater than a(k1) such that 2a(k)+1 is prime and a(k)+a(j)+1 is prime for all 1<=j<k. Let A(1)=A119751, that is, A(1,k)=A119751(k). Then A(n) is the sequence defined recursively as follows: (1) A(n,1) is the first odd number not in any A(m), 1<=m<n, such that 2A(n,1)+1 is prime. (2) A(n,k) is the first odd number greater than A(n,k1), not in any A(m), 1<=m<n, such that 2A(n,k)+1 is prime. (3) A(n,k)+A(n,j)+1 is prime for all 1<=j<k.


1



1, 5, 15, 23, 33, 41, 53, 75, 89, 99, 105, 113, 153, 155, 165, 189, 215, 239, 249, 261, 281, 293, 323, 341, 363, 371, 375, 405, 411, 419, 431, 473, 519, 543, 545, 561, 575, 629, 659, 699, 725, 741, 743, 765, 785, 803, 831, 849, 893, 905, 915, 923, 933, 935
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OFFSET

1,2


LINKS

Table of n, a(n) for n=1..54.


EXAMPLE

a(1)=1 is the first element of A119751=1, 3, 9, 69, 429, 4089, 86529, 513099, ... so a(2)=5 since 5 is the first odd number not in A119751 such that 2*5+1 is prime. Furthermore, A(2)=5, 11, 35, 95, 221, 551, 1271, 5705,...


CROSSREFS

Cf. A119751, A119752, A127257.
Sequence in context: A328249 A110702 A141394 * A136139 A029480 A029504
Adjacent sequences: A127253 A127254 A127255 * A127257 A127258 A127259


KEYWORD

nonn


AUTHOR

Walter Kehowski, Jan 10 2007


STATUS

approved



