A007702 a(n) = prime(n)*...*prime(m), the least product of consecutive primes which is non-deficient.

6, 15015, 33426748355, 1357656019974967471687377449, 7105630242567996762185122555313528897845637444413640621

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..14

Formula

a(n) = Product_{k = n..A007684(n)} prime(k) = Product_{0 <= i < A107705(n)} prime(n+i). - M. F. Hasler, 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) A007702(n, p=prime(n), s=1+1/p, P=p)={until(2<=s*=1+1/p, P*=p=nextprime(p+1)); P} \\ M. F. Hasler, Jun 15 2017

Crossrefs

Cf. A005100, A007741, A007684, A007686.

Cf. A107705, A108227, A285993.

Sequence in context: A093897 A062782 A036773 * A112642 A130434 A121571

Adjacent sequences: A007699 A007700 A007701 * A007703 A007704 A007705

Keyword

nonn

Author

Walter Nissen

Extensions

More terms from Don Reble, Nov 10 2005

Status

approved