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Search: id:A111046
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| A111046 |
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Difference between squares of twin prime pairs. |
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+0
5
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| 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; listen)
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OFFSET
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1,1
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COMMENT
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Except for the first term 16 = 4^2, a(n) is never a square.
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FORMULA
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a(n) = A006512(n)^2 - A001359(n)^2 = A108604(n) - A108570(n) = 2*A054735(n) = 4*A014574(n-1) = 8*A040040(n-1).
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MAPLE
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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 (zerinvarylajos(AT)yahoo.com), Mar 08 2007
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MATHEMATICA
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Select[Table[Prime[n] + 1, {n, 220}], PrimeQ[ # + 1] &] *4 (*Chandler*)
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CROSSREFS
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Cf. A001359, A006512, A014574, A040040, A054735, A108570, A108604.
Sequence in context: A110228 A045875 A046434 this_sequence A029720 A024588 A120468
Adjacent sequences: A111043 A111044 A111045 this_sequence A111047 A111048 A111049
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KEYWORD
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easy,nonn
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AUTHOR
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Giovanni Teofilatto (g.teofilatto(AT)tiscalinet.it), Oct 06 2005
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EXTENSIONS
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Edited and extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Oct 12 2005
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