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A361679
A(n,k) is the n-th prime p such that p + 2^k is also prime; square array A(n,k), n>=1, k>=1, read by antidiagonals.
3
3, 3, 5, 3, 7, 11, 3, 5, 13, 17, 5, 7, 11, 19, 29, 3, 11, 13, 23, 37, 41, 3, 7, 29, 31, 29, 43, 59, 7, 11, 19, 41, 37, 53, 67, 71, 11, 13, 23, 37, 47, 43, 59, 79, 101, 7, 29, 37, 29, 43, 71, 67, 71, 97, 107, 5, 37, 59, 61, 53, 67, 107, 73, 89, 103, 137
OFFSET
1,1
LINKS
EXAMPLE
Square array A(n,k) begins:
3, 3, 3, 3, 5, 3, 3, 7, 11, 7, ...
5, 7, 5, 7, 11, 7, 11, 13, 29, 37, ...
11, 13, 11, 13, 29, 19, 23, 37, 59, 67, ...
17, 19, 23, 31, 41, 37, 29, 61, 89, 73, ...
29, 37, 29, 37, 47, 43, 53, 97, 101, 79, ...
41, 43, 53, 43, 71, 67, 71, 103, 107, 127, ...
59, 67, 59, 67, 107, 73, 83, 127, 131, 139, ...
71, 79, 71, 73, 131, 103, 101, 163, 149, 157, ...
101, 97, 89, 97, 149, 109, 113, 193, 179, 163, ...
107, 103, 101, 151, 167, 127, 149, 211, 197, 193, ...
MAPLE
A:= proc() option remember; local f; f:= proc() [] end;
proc(n, k) option remember; local p;
p:= `if`(nops(f(k))=0, 1, f(k)[-1]);
while nops(f(k))<n do p:= nextprime(p);
if isprime(p+2^k) then f(k):= [f(k)[], p] fi
od; f(k)[n]
end
end():
seq(seq(A(n, 1+d-n), n=1..d), d=1..12);
CROSSREFS
Row n=1 gives A056206.
Main diagonal gives A361680.
Cf. A000040.
Sequence in context: A360469 A320045 A334481 * A351561 A029620 A204100
KEYWORD
nonn,look,tabl
AUTHOR
Alois P. Heinz, Mar 20 2023
STATUS
approved