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 A158509 Prime(n-1) such that prime(n-1)+5 is square and equal to prime(n+1)-1. 0
 11, 191, 495611, 1628171, 1893371, 7806431, 14167691, 15085451, 16048031, 20124191, 23951231, 27415691, 28558331, 30096191, 41396351, 46022651, 55591931, 87871871, 88811771, 99720191, 103347551, 130051211 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,1 COMMENTS Conjecture: If the condition holds, prime(n-1) and prime(n) are twin primes of the form 10k+1 and 10k+3. Ie., the last digits of the primes are 1 and 3. The 1 ending is evident in the entries here. LINKS S. M. Ruiz, Integer then equal. FORMULA Prime(n) is the n-th prime number. EXAMPLE For n = 6, prime(6-1)=11,11+5=16;prime(6+1)=17,17-1=16. So prime(6-1)=11 is the first entry in the sequence. PROG (PARI) integerequal(m, n, a, b) = { local(x, p1, p2); for(x=m, n, p1=prime(x-1); if(issquare(p1+a), p2=prime(x+1); if((p1+a)==(p2-b), print(x", "p1", "prime(x)) ) ) ) } CROSSREFS Sequence in context: A002195 A171553 A068649 * A072290 A213691 A112127 Adjacent sequences:  A158506 A158507 A158508 * A158510 A158511 A158512 KEYWORD nonn AUTHOR Cino Hilliard (hillcino368(AT)hotmail.com), Mar 20 2009 STATUS approved

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