|
Search: id:A154669
|
|
|
| A154669 |
|
Averages of twin prime pairs n such that 2*n^3+12*n^2 is a square. |
|
+0
1
|
|
| 12, 282, 642, 1452, 12162, 17292, 34842, 98562, 194682, 233922, 347772, 383682, 410412, 544962, 749082, 1071642, 1302492, 1421292, 1503372, 1685442, 2794242, 3011052, 3235962, 3312732, 3792252, 3875322, 4755522
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
COMMENT
|
11,12,13;Sqrt[2*12^3+12*12^2]=72,...
|
|
MAPLE
|
a := proc (n) if isprime(n-1) = true and isprime(n+1) = true and type(sqrt(2*n^3+12*n^2), integer) = true then n else end if end proc: seq(a(n), n = 3 .. 5000000); [From Emeric Deutsch (deutsch(AT)duke.poly.edu), Jan 20 2009]
|
|
MATHEMATICA
|
a[n_]:=Sqrt[2*n^3+12*n^2]; lst={}; Do[If[Floor[a[n]]==a[n], If[PrimeQ[n-1]&&PrimeQ[n+1], AppendTo[lst, n]]], {n, 9!}]; lst
|
|
CROSSREFS
|
Cf. A152811
Sequence in context: A115461 A166337 A009604 this_sequence A079519 A077424 A159827
Adjacent sequences: A154666 A154667 A154668 this_sequence A154670 A154671 A154672
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Vladimir Orlovsky (4vladimir(AT)gmail.com), Jan 13 2009
|
|
EXTENSIONS
|
Extended by Emeric Deutsch (deutsch(AT)duke.poly.edu), Jan 20 2009
|
|
|
Search completed in 0.002 seconds
|
