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A154675 Averages of twin prime pairs n such that n*13 and n/13 are squares. 2
1872, 7488, 11700, 825552, 990288, 1123668, 1629108, 3146832, 3302208, 4680000, 6627348, 7667712, 8783892, 15502032, 16017300, 16365492, 17252352, 25407252, 32617728, 42401268, 42966612, 54100800, 66163968, 71182800, 73019700 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Terms of this sequence must be of the form 13(6m)^2, the values for m are listed in A154775. - M. F. Hasler, Jan 15 2009

LINKS

Table of n, a(n) for n=1..25.

FORMULA

a(n) = 468 A154775(n)^2 - M. F. Hasler, Jan 15 2009

MATHEMATICA

lst={}; Do[If[PrimeQ[n-1]&&PrimeQ[n+1], s=(n*13)^(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/13)^(1/2); If[Floor[s]==s, AppendTo[lst, n]]], {n, 6, 11!, 6}]; lst

PROG

(PARI) for(i=1, 499, isprime(468*i^2+1) && isprime(468*i^2-1) && print1(468*i^2", ")) \\ M. F. Hasler, Jan 15 2009

CROSSREFS

Cf. A154670, A154671, A154672, A154673, A154674.

Sequence in context: A232040 A054817 A270244 * A068281 A139668 A244019

Adjacent sequences:  A154672 A154673 A154674 * A154676 A154677 A154678

KEYWORD

nonn,changed

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 June 27 19:44 EDT 2017. Contains 288790 sequences.