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 A064819 a(n) = p(1)*p(2)*...*p(n) - p(n+1)^2, where p(i) = i-th prime. 2
 -7, -19, -19, 89, 2141, 29741, 510149, 9699161, 223092029, 6469692269, 200560488761, 7420738133129, 304250263525361, 13082761331667821, 614889782588488601, 32589158477190041249, 1922760350154212635349, 117288381359406970978781 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS It is known that a(n) > 0 for n >= 4. REFERENCES R. Honsberger, Mathematical Diamonds, MAA, 2003, see p. 79. [Added by N. J. A. Sloane, Jul 05 2009] H. Rademacher & O. Toeplitz, The Enjoyment of Mathematics, pp. 187-192 Dover NY 1990. J. V. Uspensky and M. A. Heaslet, Elementary Number Theory, McGraw-Hill, NY, 1939. LINKS Harry J. Smith, Table of n, a(n) for n = 1..100 S. Bulman-Fleming and E. T. H. Wang, Problem 356, College Math. J., 20 (1989), 265. Wikipedia, Bonse's inequality PROG (PARI) { p=1; for (n=1, 100, p*=prime(n); write("b064819.txt", n, " ", p - prime(n + 1)^2) ) } \\ Harry J. Smith, Sep 27 2009 (PARI) a(n) = prod(k=1, n, prime(k)) - prime(n+1)^2; \\ Michel Marcus, Jun 19 2018 CROSSREFS Cf. A135734, A060882. Sequence in context: A195867 A344711 A052256 * A281915 A102167 A214525 Adjacent sequences:  A064816 A064817 A064818 * A064820 A064821 A064822 KEYWORD sign AUTHOR N. J. A. Sloane, Oct 23 2001 STATUS approved

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Last modified January 19 21:38 EST 2022. Contains 350466 sequences. (Running on oeis4.)