

A111046


Difference between squares of twin prime pairs.


7



16, 24, 48, 72, 120, 168, 240, 288, 408, 432, 552, 600, 720, 768, 792, 912, 960, 1080, 1128, 1248, 1392, 1680, 1728, 1848, 2088, 2280, 2400, 2472, 2568, 2640, 3240, 3288, 3312, 3432, 3528, 4080, 4128, 4200, 4248, 4368, 4608, 4920, 5112, 5160, 5208, 5280
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,1


COMMENTS

Except for the first term 16 = 4^2, a(n) is never a square.


LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000


FORMULA

a(n) = A006512(n)^2  A001359(n)^2 = A108604(n)  A108570(n) = 2*A054735(n) = 4*A014574(n) = 8*A040040(n).


MAPLE

ZL:=[]:for p from 1 to 1400 do if (isprime(p) and isprime(p+2)) then ZL:=[op(ZL), (((p+2)^2)p^2)]; fi; od; print(ZL); # Zerinvary Lajos, Mar 08 2007


MATHEMATICA

Select[Table[Prime[n] + 1, {n, 220}], PrimeQ[ # + 1] &] *4 (* Ray Chandler, Oct 12 2005 *)
4+4#&/@Select[Partition[Prime[Range[300]], 2, 1], #[[2]]#[[1]]==2&] [[All, 1]] (* Harvey P. Dale, Apr 12 2018 *)


PROG

(Haskell)
a111046 = (* 2) . a054735  Reinhard Zumkeller, Feb 10 2015


CROSSREFS

Cf. A001359, A006512, A014574, A040040, A054735, A108570, A108604.
Sequence in context: A175161 A045875 A046434 * A205187 A162819 A029720
Adjacent sequences: A111043 A111044 A111045 * A111047 A111048 A111049


KEYWORD

easy,nonn


AUTHOR

Giovanni Teofilatto, Oct 06 2005


EXTENSIONS

Edited and extended by Ray Chandler, Oct 12 2005


STATUS

approved



