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A138923
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Indices k such that A020506(k)=Phi[k](-7) is prime, where Phi is a cyclotomic polynomial.
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2
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3, 9, 10, 15, 17, 23, 25, 26, 27, 28, 29, 36, 42, 47, 48, 61, 76, 84, 110, 126, 148, 210, 224, 262, 280, 288, 296, 298, 325, 327, 332, 352, 365, 456, 513, 528, 740, 1062, 1162, 1445, 1460, 1518, 1619, 1660, 2094, 2130, 2260, 2380, 3398, 3447, 3918
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OFFSET
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1,1
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COMMENTS
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There are only 6 terms between 365 and 1445 (exclusive).
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LINKS
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MATHEMATICA
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PROG
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(PARI) for( i=1, 999, ispseudoprime( polcyclo(i, -7)) && print1( i", ")) /* use ...subst(polcyclo(i), x, -7)... in PARI < 2.4.2 */
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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