OFFSET
1,1
COMMENTS
A permutation of the prime numbers.
Is this the same as k-th prime p such that A001221(2^p-1) = n?
EXAMPLE
Array starts
2, 3, 5, 7, 13, 17, ....
11, 23, 37, 41, 59, 67, ....
29, 43, 47, 53, 71, 73, ....
157, 173, 181, 229, 233, 263, ....
113, 151, 163, 191, 251, 307, ....
223, 239, 359, 463, 587, 641, ....
....
A(2, 3) = 37, because the 3rd prime p such that 2^p-1 has 2 prime factors is 37, with 2^37-1 = 223 * 616318177.
MATHEMATICA
With[{s = Array[PrimeOmega[2^Prime@ # - 1] &, 50]}, Function[t, Function[u, Table[Prime@ u[[#, k]] &[n - k + 1], {n, Length@t}, {k, n, 1, -1}]]@ Map[PadRight[#, Length@ t] &, t]]@ Values@ KeySort@ PositionIndex@ s] // Flatten (* Michael De Vlieger, Sep 17 2017 *)
CROSSREFS
KEYWORD
AUTHOR
Felix Fröhlich, Sep 17 2017
EXTENSIONS
More terms from Michael De Vlieger, Sep 17 2017
STATUS
approved