A177680 Numbers n such that 6n and 12n are both the average of twin prime pairs.

1, 5, 110, 135, 355, 425, 555, 565, 975, 1045, 1755, 5530, 6935, 7355, 8925, 9240, 9555, 10640, 10850, 11730, 11830, 12045, 12350, 12460, 13130, 13445, 13655, 14590, 15540, 17050, 19245, 20795, 22330, 22825, 26070, 26910, 28075, 30585, 30805

Offset

1,2

Comments

Conjecture: all terms but the first term are multiples of 5. - Harvey P. Dale, Sep 26 2017

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Formula

a(n)=A066388(n)/6.

Example

a(1)=1 because 6*1-1=5, 6*1+1=7, 12*1-1=11 and 12*1+1=13 are all twin primes.

Mathematica

Select[Range[31000], AllTrue[Flatten[{6*#+{1, -1}, 12*#+{1, -1}}], PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Sep 26 2017 *)

Crossrefs

Cf. A014574.

Sequence in context: A245106 A244004 A003465 * A281762 A265082 A215786

Adjacent sequences: A177677 A177678 A177679 * A177681 A177682 A177683

Keyword

nonn

Author

Juri-Stepan Gerasimov, May 10 2010

Extensions

Corrected (13590 removed, 13655 and 14590 inserted, 22725 replaced by 22825) by R. J. Mathar, May 15 2010

Status

approved