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A255230
Integers n such that n^2 = 2*x*(y-x), where x and y are consecutive terms in A014574.
0
4, 12, 48, 120, 468, 1260, 720, 2448, 10080, 12060, 15912, 7560, 18480, 7392, 9660, 27720, 33480, 14400, 25080, 36708, 10092, 34188, 42120, 83400, 29820, 20040, 67320, 114408, 206628, 67368, 72192, 102648, 152928, 51732, 59880, 152700, 106440, 100980, 171480
OFFSET
1,1
COMMENTS
n is a term if n^2 = 2*x*(y-x), where x and y are the averages of two consecutive twin prime pairs.
EXAMPLE
48^2 = 2*192*(198-192), and 192 and 198 are consecutive terms in A014574, so 48 is in the sequence.
PROG
(PARI) lista(nn) = {p=2; last = 0; forprime (q=3, nn, if (q-p==2, if (! last, last = p+1, new = p+1; val = new^2-last^2 - (new-last)^2; if (issquare(val), print1(sqrtint(val), ", ")); last = new; ); ); p=q; ); } \\ Michel Marcus, Feb 18 2015
CROSSREFS
Cf. A014574.
Sequence in context: A361428 A032380 A057346 * A253087 A262414 A081620
KEYWORD
nonn
AUTHOR
Neri Gionata, Feb 18 2015
EXTENSIONS
More terms from Michel Marcus, Feb 18 2015
STATUS
approved