A255230 Integers n such that n^2 = 2*x*(y-x), where x and y are consecutive terms in A014574.

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.

Links

Table of n, a(n) for n=1..39.

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

Adjacent sequences: A255227 A255228 A255229 * A255231 A255232 A255233

Keyword

nonn

Author

Neri Gionata, Feb 18 2015

Extensions

More terms from Michel Marcus, Feb 18 2015

Status

approved