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A117344 Squarefree numbers n such that 2*n+1 is also squarefree. 1
1, 2, 3, 5, 6, 7, 10, 11, 14, 15, 17, 19, 21, 23, 26, 29, 30, 33, 34, 35, 38, 39, 41, 42, 43, 46, 47, 51, 53, 55, 57, 59, 61, 65, 66, 69, 70, 71, 74, 77, 78, 79, 82, 83, 86, 89, 91, 93, 95, 97, 101, 102, 105, 106, 107, 109, 110, 111, 113, 114, 115, 118, 119, 123, 127, 129 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

COMMENTS

a(n) = (A117203(n) - 1)/2.

CROSSREFS

Sequence in context: A137313 A028805 A117204 * A129127 A078135 A073328

Adjacent sequences:  A117341 A117342 A117343 * A117345 A117346 A117347

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Mar 09 2006

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Last modified February 13 10:09 EST 2012. Contains 205451 sequences.