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

6, 15015, 33426748355, 1357656019974967471687377449, 7105630242567996762185122555313528897845637444413640621

Offset: 1

Author

Walter Nissen

Keywords

• nonn

Links

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

Crossrefs

Cf. A005100, A007741, A007684, A007686.

Cf. A107705, A108227, A285993.

Programs

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 *)

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

Formula

a(n) = Product_{k = n..A007684(n)} prime(k) = Product_{0 <= i < A107705(n)} prime(n+i). - M. F. Hasler, Jun 15 2017

Extensions

More terms from Don Reble, Nov 10 2005