A232170 Squarefree numbers (A005117) of form prime(k)*q where q = primes of the form prime(k) + k.

6, 15, 77, 247, 4819, 7979, 10057, 12827, 21353, 24047, 40363, 60433, 121411, 146231, 154729, 211763, 273509, 301297, 322499, 346781, 367063, 382937, 394091, 415693, 453727, 485237, 579727, 632579, 803017, 874219, 910073, 1009823, 1218053, 1335181, 1740329

Offset

1,1

Comments

Let p(m) = prime(m), let i(p(m)) = m, the subscript of p(m); a(n) = squarefree numbers with 2 prime factors of the form p_1 * p_2 where p_1 < p_2 with p_2 = p_1 + i(p_1).

Subsequence of A232169.

Links

Jaroslav Krizek, Table of n, a(n) for n = 1..900

Example

 Number 10057 = 89 * 113 is in sequence because 89 = prime(24) and 113 = 89 + 24.

Crossrefs

Cf. A000040, A005117, A232169, A232171.

Sequence in context: A032164 A177122 A108540 * A165570 A260117 A220360

Adjacent sequences: A232167 A232168 A232169 * A232171 A232172 A232173

Keyword

nonn

Author

Jaroslav Krizek, Nov 19 2013

Status

approved