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A129215
Numbers m such that 9!*m -+ 1 are twin primes.
4
3, 11, 22, 38, 52, 69, 125, 140, 154, 167, 169, 185, 198, 200, 205, 239, 299, 308, 335, 368, 376, 390, 405, 421, 482, 509, 574, 597, 610, 663, 684, 700, 701, 720, 763, 792, 795, 798, 840, 843, 855, 898, 907, 921, 954, 957
OFFSET
1,1
LINKS
FORMULA
9!*a(n) are terms in A014574.
MATHEMATICA
s={}; Do[m=362880k; If[PrimeQ[m-1]&&PrimeQ[m+1], AppendTo[s, k]], {k, 1000}]; s
With[{c=9!}, Select[Range[1000], And@@PrimeQ[c*#+{1, -1}]&]] (* Harvey P. Dale, Aug 27 2013 *)
PROG
(Magma) [m:m in [1..1000]| IsPrime(Factorial(9)*m+1) and IsPrime(Factorial(9)*m-1)]; // Marius A. Burtea, Dec 29 2019
CROSSREFS
Cf. A014574 (average of twin prime pairs), A127545 (multiples of 7 in A014574), A137877.
Numbers m such that (N!*m -+ 1) are twin primes: A129213 (N=7), A129214 (N=8), A129216 (N=10).
Sequence in context: A184053 A240371 A158653 * A139593 A121471 A293766
KEYWORD
nonn
AUTHOR
Zak Seidov, Apr 03 2007
STATUS
approved