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A074822 Primes p such that p + 4 is prime and p == 9 (mod 10). 15
19, 79, 109, 229, 349, 379, 439, 499, 739, 769, 859, 1009, 1279, 1429, 1489, 1549, 1579, 1609, 1999, 2239, 2269, 2389, 2539, 2659, 2689, 2749, 3019, 3079, 3319, 3529, 3919, 4129, 4519, 4639, 4729, 4789, 4969, 4999, 5479, 5569, 5689, 5779, 5839, 6199 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Also primes for which k is equal to 5 in A117078. Examples: prime(9) = prime(8) + (prime(8) mod 5) = 19 + (19 mod 5)=23; prime(23) = prime(22) + (prime(22) mod 5) = 79 + (79 mod 5)=83; prime(1359) = prime(1358) + (prime(1358) mod 5) = 11239+ (11239 mod 5)=11243 - Rémi Eismann, May 14 2006

The prime numbers in this sequence are of the form (10i-1) with i=(level(n)+1)/2, level(n) defined in A117563. - Rémi Eismann, May 14 2006, May 04 2007

Consider A117078: a(n) = smallest k such that prime(n+1) = prime(n) + (prime(n) mod k), or 0 if no such k exists. Sequence gives values of prime(n) for which k=5. - Rémi Eismann, May 14 2006

LINKS

Remi Eismann, Table of n, a(n) for n = 1..10000

MATHEMATICA

Prime[ Select[ Range[1000], Prime[ # ] + 4 == Prime[ # + 1] && Mod[ Prime[ # ], 10] == 9 & ]]

Transpose[Select[Partition[Prime[Range[820]], 2, 1], Last[#]-First[#] == 4&&Mod[First[#], 10]==9&]][[1]] (* Harvey P. Dale, Oct 20 2011 *)

CROSSREFS

Cf. A117078, A074822, A001223, A117563, A001359, A118359, A118922, A118924, A119504.

Sequence in context: A041700 A213832 A132234 * A139871 A142789 A158491

Adjacent sequences:  A074819 A074820 A074821 * A074823 A074824 A074825

KEYWORD

nonn

AUTHOR

Roger L. Bagula, Sep 30 2002

EXTENSIONS

Edited by Robert G. Wilson v and N. J. A. Sloane, Oct 03 2002

Entry revised by N. J. A. Sloane, Feb 24 2007

STATUS

approved

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Last modified May 26 07:30 EDT 2017. Contains 287093 sequences.