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 A138937 Indices k such that A019325(k)=Phi[k](7) is prime, where Phi is a cyclotomic polynomial. 3
 5, 6, 13, 18, 21, 28, 30, 34, 36, 46, 48, 50, 54, 55, 58, 63, 76, 84, 94, 105, 122, 131, 148, 149, 224, 280, 288, 296, 332, 352, 456, 528, 531, 581, 650, 654, 730, 740, 759, 1026, 1047, 1065, 1460, 1660, 1699, 1959, 2067, 2260, 2380, 2665, 2890, 3238, 4020 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Robert Price, Table of n, a(n) for n = 1..95 Yves Gallot, Cyclotomic polynomials and prime numbers MATHEMATICA Select[Range[1000], PrimeQ[Cyclotomic[#, 7]] &] PROG (PARI) for( i=1, 999, ispseudoprime( polcyclo(i, 7)) && print1( i", ")) /* use ...subst(polcyclo(i), x, 7)... in PARI < 2.4.2 */ CROSSREFS Cf. A019325, A138920-A138940. Sequence in context: A303139 A322611 A030356 * A314291 A314292 A294572 Adjacent sequences:  A138934 A138935 A138936 * A138938 A138939 A138940 KEYWORD nonn AUTHOR M. F. Hasler, Apr 03 2008 EXTENSIONS a(40)-a(53) from Robert Price, Apr 18 2012 STATUS approved

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Last modified May 31 13:01 EDT 2020. Contains 334748 sequences. (Running on oeis4.)