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 A035790 Start of a string of exactly 2 consecutive (but disjoint) pairs of twin primes. 11
 101, 137, 419, 1019, 1049, 1481, 1871, 1931, 2081, 2111, 2969, 3251, 3461, 4259, 5009, 5651, 5867, 6689, 6947, 7331, 7547, 8219, 8969, 10007, 11057, 11159, 11699, 12239, 13001, 13709, 13997, 14561, 15641, 15731, 16061, 16631, 17579, 17909 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Let P1,P2,..,P8 be any 8 consecutive primes. The sequence consists of those values of P3 for which P2-P1>2, P4-P3=2, P6-P5=2 and P8-P7>2. REFERENCES Posting to Number Theory List (NMBRTHRY(AT)LISTSERV.NODAK.EDU), Nov. 19 1998. LINKS Sebastian Petzelberger, Table of n, a(n) for n = 1..10000 G. L. Honaker, Jr. and Chris Caldwell, 10000...01521 (100-digits) Hugo Pfoertner, FORTRAN program: Consecutive pairs of twin primes. FORMULA a(10)=2111, a(10^2)=77261, a(10^3)=1603697, a(10^4)=27397631, a(10^5)=435140477, a(10^6)=6391490657. - M. F. Hasler, May 04 2015 EXAMPLE 89, 97, 101, 103, 107, 109, 113, 127: 97-89>2, 103-101=2, 109-107=2, 127-113>2. MATHEMATICA Select[Prime@ Range@ 2100, And[NextPrime[#, -1] - NextPrime[#, -2] > 2, NextPrime@ # - # == 2, NextPrime[#, 3] - NextPrime[#, 2] == 2, NextPrime[#, 5] - NextPrime[#, 4] > 2] &] (* Michael De Vlieger, Apr 25 2015 *) PROG (PARI) a(n)={L=vector(7); forprime(p=o=1, , L=concat(L[2..7], -o+o=p); L[3]==2&&L[5]==2&&L[1]>2&&L[2]>2&&L[4]>2&&L[6]>2&&L[7]>2&&!n--&&return(p-sum(i=3, 7, L[i])))} \\ - M. F. Hasler, May 04 2015 CROSSREFS Cf. A035789, A035791, A035792, A035793, A035794, A035795, A087641. Sequence in context: A104946 A272075 A162463 * A139489 A106994 A050672 Adjacent sequences:  A035787 A035788 A035789 * A035791 A035792 A035793 KEYWORD nonn,easy AUTHOR Randall Rathbun, Nov 30 1998 EXTENSIONS Edited by Hugo Pfoertner, Oct 15 2003 Offset corrected by Arkadiusz Wesolowski, May 06 2012 Double-checked up to a(10^4)=27397631 by M. F. Hasler, May 04 2015 STATUS approved

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Last modified May 24 15:25 EDT 2019. Contains 323532 sequences. (Running on oeis4.)