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 A074822 Primes p such that p + 4 is prime and p == 9 (mod 10). 18
 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 From Rémi Eismann, May 14 2006; May 04 2007: (Start) 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. The prime numbers in this sequence are of the form (10i-1) with i=(level(n)+1)/2, level(n) defined in A117563. 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. (End) p is the lesser member of cousin primes (p,p+4) such that p == 9 (mod 10). - Muniru A Asiru, Jul 03 2017 LINKS Remi Eismann, Table of n, a(n) for n = 1..10000 Eric Weisstein's World of Mathematics, Cousin Primes 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 *) PROG (PARI) is(n)=n%30==19 && isprime(n+4) && isprime(n) \\ Charles R Greathouse IV, Jul 12 2017 (PARI) list(lim)=my(v=List(), p=19); forprime(q=23, lim+4, if(q-p==4 && p%30==19, listput(v, p)); p=q); Vec(v) \\ Charles R Greathouse IV, Jul 12 2017 CROSSREFS Cf. A001223, A117078, A117563. Intersection of A023200 and A030433. Sequence in context: A213832 A350194 A132234 * A139871 A142789 A158491 Adjacent sequences: A074819 A074820 A074821 * A074823 A074824 A074825 KEYWORD nonn,easy 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 December 3 08:35 EST 2022. Contains 358515 sequences. (Running on oeis4.)