A261655 Squares equal to the difference between two successive primes of the form k^2+2 in the order in which they appear in A056899.
1, 144, 1296, 3600, 176400, 156816, 2985984, 921600, 2702736, 11696400, 18974736, 21566736, 17740944, 5992704, 125888400, 7290000, 8363664, 12027024, 63680400, 210830400, 13838400, 72590400, 15116544, 15397776, 67568400, 128595600, 80784144, 93315600, 33039504
Offset: 1
Keywords
Examples
A056899(2)- A056899(1) = 3-2 = 1^2; A056899(5)- A056899(4) = 227-83 = 144 = 12^2; A056899(14)- A056899(13) = 12323-11027 = 1296 = 36^2.
Links
- Robert G. Wilson v, Table of n, a(n) for n = 1..1100
Programs
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Maple
q:=2:for n from 1 to 10^7 do:p:=n^2+2:if isprime(p) then x:=p-q:q:=p: z:=sqrt(x):if z=floor(z) then printf(`%d, `, x):else fi:fi:od:
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Mathematica
Select[ Differences[ Select[ Range[0, 1000000], PrimeQ[#^2 + 2] &]^2], IntegerQ@ Sqrt@# &] (* or *) k = 1; p = 3; lst = {1}; While[k < 10000001, q = (6k +3)^2 + 2; If[ PrimeQ@ q, If[ IntegerQ@ Sqrt[q - p], AppendTo[lst, q - p]]; p = q]; k++] (* Robert G. Wilson v, Sep 03 2015 *)
Comments