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 A007741 a(n) = prime(n)*...*prime(m), the least product of consecutive primes which is abundant. 12
 30, 15015, 33426748355, 1357656019974967471687377449, 7105630242567996762185122555313528897845637444413640621 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Essentially, i.e., except for a(1), identical to A007702. All terms are primitive abundant numbers (A091191) and thus, except for the first term, odd primitive abundant (A006038). The next term is too large to be displayed here, see A007707 (and formula) for many more terms, using a more compact encoding. - M. F. Hasler, Apr 30 2017 LINKS Amiram Eldar, Table of n, a(n) for n = 1..14 G. Thimm, Emails to N. J. A. Sloane, Sep. 1994 FORMULA a(n) = Product_{k=n..A007707(n)} prime(k) = Product_{0 <= i < A108227(n)} prime(n+i). - M. F. Hasler, Apr 30 2017 and Jun 15 2017 MATHEMATICA a[n_] := Module[{p = Prime[n]}, r = 1; prod = 1; While[r <= 2, r *= 1 + 1/p; prod *= p; p = NextPrime[p]]; prod]; Array[a, 5] (* Amiram Eldar, Jun 29 2019 *) PROG (PARI) a(n) = {p = prime(n); sig = p+1; prd = p; while (sig <= 2*prd, p = nextprime(p+1); sig *= p+1; prd *= p; ); return (prd); } \\ Michel Marcus, Mar 10 2013 CROSSREFS Cf. A005101, A006038, A007702, A007707, A007708, A091191. Cf. A108227, A285993. Sequence in context: A294979 A250435 A137749 * A176378 A089037 A116076 Adjacent sequences:  A007738 A007739 A007740 * A007742 A007743 A007744 KEYWORD nonn AUTHOR EXTENSIONS More terms from Don Reble, Nov 10 2005 STATUS approved

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Last modified November 22 10:59 EST 2019. Contains 329389 sequences. (Running on oeis4.)