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A128471 30*n+7. 2
7, 37, 67, 97, 127, 157, 187, 217, 247, 277, 307, 337, 367, 397, 427, 457, 487, 517, 547, 577, 607, 637, 667, 697, 727, 757, 787, 817, 847, 877, 907, 937, 967, 997, 1027, 1057, 1087, 1117, 1147, 1177, 1207, 1237, 1267, 1297, 1327, 1357, 1387, 1417, 1447, 1477 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

30*n+7 -/+ 2 is a multiple of 3 or 5. For n > 0, this number is not prime. So with the exception of a(0), no a(n) is a member of a twin prime pair.

Except for 7, these numbers cannot be written as sum or difference of two primes. [Arkadiusz Wesolowski, Jan 08 2012]

LINKS

Table of n, a(n) for n=0..49.

Counting Twin Primes

Index entries for linear recurrences with constant coefficients, signature (2,-1).

FORMULA

a(n) = 2*a(n-1)-a(n-2). [Vincenzo Librandi, Sep 05 2010]

G.f. (7+23*x)/(1-x)^2. [R. J. Mathar, Sep 05 2010]

MATHEMATICA

Range[7, 7000, 30] (* Vladimir Joseph Stephan Orlovsky, Jun 18 2011 *)

PROG

(PARI) A128471(n)={ return(30*n+7) ; }

for(n=0, 30, print1(A128471(n)", ")) ; /* R. J. Mathar, Sep 05 2010 */

CROSSREFS

Sequence in context: A032588 A123084 A123085 * A168003 A132231 A221982

Adjacent sequences:  A128468 A128469 A128470 * A128472 A128473 A128474

KEYWORD

easy,nonn

AUTHOR

Cino Hilliard, May 06 2007

EXTENSIONS

Comment clarified by R. Israel, offset set to zero by R. J. Mathar, Sep 05 2010

STATUS

approved

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Last modified March 28 02:40 EDT 2017. Contains 284182 sequences.