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 A166945 Records of first differences of A166944. 15
 2, 3, 7, 13, 43, 139, 313, 661, 1321, 2659, 5419, 10891, 22039, 44383, 88801, 177841, 355723, 713833, 1427749, 2860771, 5725453, 11461141, 22933441, 45895573, 91793059, 183616423, 367232911, 734482123, 1468965061, 2937930211, 5875882249, 11751795061, 23503590559, 47007181621, 94014363763 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Conjecture. Each term of the sequence is the greater of a pair of twin primes (A006512). LINKS E. S. Rowland, A natural prime-generating recurrence, Journal of Integer Sequences, Vol.11(2008), Article 08.2.8. arXiv:0710.3217 [math.NT] V. Shevelev, An infinite set of generators of primes based on the Rowland idea and conjectures concerning twin primes, arXiv:0910.4676 [math.NT], 2009. V. Shevelev, Three theorems on twin primes, arXiv:0911.5478 [math.NT], 2009-2010. MATHEMATICA Reap[Print[old = r = 2]; Sow[old]; For[n = 2, n <= 10^6, n++, d = GCD[old, If[OddQ[n], n-2, n]]; If[d>r, r=d; Print[d]; Sow[d]]; old += d]][[2, 1]] (* Jean-François Alcover, Nov 03 2018, from PARI *) PROG (PARI) print1(old=r=2); for(n=2, 1e11, d=gcd(old, if(n%2, n-2, n)); if(d>r, r=d; print1(", "d)); old+=d) \\ Charles R Greathouse IV, Oct 13 2017 CROSSREFS Cf. A166944, A084662, A084663, A106108, A132199, A134162, A135506, A135508, A118679, A120293. Sequence in context: A007996 A206579 A349327 * A257393 A273814 A085872 Adjacent sequences: A166942 A166943 A166944 * A166946 A166947 A166948 KEYWORD nonn AUTHOR Vladimir Shevelev, Oct 24 2009, Nov 05 2009 EXTENSIONS 6 more terms from R. J. Mathar, Nov 19 2009; extension beginning with a(19) from Benoit Cloitre (private communication to Vladimir Shevelev) a(25), a(26) from D. S. McNeil, Dec 13 2010 a(27)-a(30) from Charles R Greathouse IV, Oct 13 2017 a(31)-a(35) from Charles R Greathouse IV, Oct 17 2017 STATUS approved

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Last modified March 28 17:47 EDT 2023. Contains 361596 sequences. (Running on oeis4.)