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 A084968 Multiples of 7 coprime to 30. 8
 7, 49, 77, 91, 119, 133, 161, 203, 217, 259, 287, 301, 329, 343, 371, 413, 427, 469, 497, 511, 539, 553, 581, 623, 637, 679, 707, 721, 749, 763, 791, 833, 847, 889, 917, 931, 959, 973, 1001, 1043, 1057, 1099, 1127, 1141, 1169, 1183, 1211, 1253, 1267, 1309 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Fourth row of A083140. LINKS Index entries for linear recurrences with constant coefficients, signature (1,0,0,0,0,0,0,1,-1). FORMULA GCD( 7k, 30) =1. G.f.: 7*x*(x^8+6*x^7+4*x^6+2*x^5+4*x^4+2*x^3+4*x^2+6*x+1) / ((x-1)^2*(x+1)*(x^2+1)*(x^4+1)). [Colin Barker, Feb 24 2013] lim a(n)/n = A038111(4)/A038110(4) = 26.25 as n goes to infinity. - Vladimir Shevelev, Jan 20 2015 EXAMPLE 77 is in the sequence because gcd(77, 30) = 1. 84 is not in the sequence because gcd(84, 3) = 6. 91 is in the sequence because gcd(91, 30) = 1. MATHEMATICA 7Select[ Range, GCD[ #, 2*3*5] == 1 & ] PROG (PARI) is(n)=gcd(210, n)==7 \\ Charles R Greathouse IV, Aug 05 2013 CROSSREFS Subsequence of A008589. Cf. A083140, A007775. Sequence in context: A083930 A178367 A036132 * A161145 A230655 A008461 Adjacent sequences:  A084965 A084966 A084967 * A084969 A084970 A084971 KEYWORD nonn,easy AUTHOR Robert G. Wilson v, Jun 15 2003 STATUS approved

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Last modified March 26 10:57 EDT 2019. Contains 321491 sequences. (Running on oeis4.)