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A232170 Squarefree numbers (A005117) of form prime(k)*q where q = primes of the form prime(k) + k. 3
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified June 24 21:36 EDT 2021. Contains 345430 sequences. (Running on oeis4.)