A122139 Primes from A122136[n] corresponding to the indices A122138[n].

2, 13, 19, 29, 29, 79, 47, 73, 163, 359, 5233, 20477, 811, 13859, 2203, 75997, 3331, 4457, 239087, 58061, 159097, 116041, 7487, 17929, 4547, 152657, 408787, 58313, 5563, 4783, 226199, 13729, 676763, 204641, 119293, 283979, 2210983, 7121, 433

Offset

1,1

Comments

A122136[n] = Numerator of Sum[ Prime[k]^2, {k,1,n}] / Product[ Prime[k], {k,1,n}] ] = Numerator[ A024450[n] / A002110[n] ]. A122136[n] begins {2,13,19,29,104,29,111,79,778,47,73,163,1068,359,5233,885,142,20477,219,811,...}. A122138[n] lists the indices n such that A122136[n] is a prime {1,2,3,4,6,8,10,11,12,14,15,18,20,22,23,26,27,32,36,...}.

Links

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

Formula

a(n) = A122136[ A122138[n] ].

Mathematica

Select[Table[Numerator[Sum[Prime[k]^2, {k, 1, n}]/Product[Prime[k], {k, 1, n}]], {n, 1, 200}], PrimeQ[ #1]&]

Crossrefs

Cf. A122136, A122138, A024450, A002110.

Sequence in context: A119570 A018485 A097234 * A122136 A168672 A297854

Adjacent sequences: A122136 A122137 A122138 * A122140 A122141 A122142

Keyword

nonn

Author

Alexander Adamchuk, Aug 21 2006

Status

approved