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A154674 Averages of twin prime pairs k such that k*11 and k/11 are squares. 5
990000, 1940400, 2227500, 6187500, 35640000, 54212400, 57182400, 74933100, 159677100, 164745900, 167310000, 194040000, 289485900, 380318400, 424205100, 496742400, 664101900, 684773100, 902919600, 976100400, 982327500, 1007433900 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = 9900*A154774(n)^2. - M. F. Hasler, Jan 15 2009

MATHEMATICA

lst={}; Do[If[PrimeQ[n-1]&&PrimeQ[n+1], s=(n*11)^(1/2); If[Floor[s]==s, AppendTo[lst, n]]], {n, 6, 11!, 6}]; lst...and/or... lst={}; Do[If[PrimeQ[n-1]&&PrimeQ[n+1], s=(n/11)^(1/2); If[Floor[s]==s, AppendTo[lst, n]]], {n, 6, 11!, 6}]; lst

Select[11*Range[10^4]^2, And @@ PrimeQ[# + {-1, 1}] &] (* Amiram Eldar, Dec 25 2019 *)

PROG

(PARI) for(i=1, 999, isprime(9900*i^2+1) && isprime(9900*i^2-1) && print1(9900*i^2", ")) \\ M. F. Hasler, Jan 15 2009

CROSSREFS

Cf. A154670, A154671, A154672, A154673, A154774.

Sequence in context: A328287 A083395 A106782 * A236034 A055617 A055618

Adjacent sequences:  A154671 A154672 A154673 * A154675 A154676 A154677

KEYWORD

nonn

AUTHOR

Vladimir Joseph Stephan Orlovsky, Jan 13 2009

EXTENSIONS

More terms from M. F. Hasler, Jan 15 2009

STATUS

approved

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Last modified November 29 01:40 EST 2021. Contains 349416 sequences. (Running on oeis4.)