A118456 a(n) = Product_{k=1..n} P(k), where P(k) is the smallest prime >= k.
2, 4, 12, 60, 300, 2100, 14700, 161700, 1778700, 19565700, 215222700, 2797895100, 36372636300, 618334817100, 10511691890700, 178698762141900, 3037878956412300, 57719700171833700, 1096674303264840300, 25223508975091326900, 580140706427100518700, 13343236247823311930100
Offset: 1
Examples
a(5)=300 because the smallest primes that are not smaller than 1,2,3,4 and 5 are 2,2,3,5 and 5, respectively, having product 2*2*3*5*5=300.
Links
- Michael De Vlieger, Table of n, a(n) for n = 1..448
Programs
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Maple
a:=n->product(nextprime(k-1),k=1..n): seq(a(n),n=1..22); # Emeric Deutsch, Apr 29 2006
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Mathematica
FoldList[Times, Table[NextPrime[k - 1], {k, 22}]] (* Michael De Vlieger, Aug 21 2017 *) -
PARI
a(n) = prod(k=1, n, nextprime(k)); \\ Michel Marcus, Aug 20 2019
Extensions
More terms from Emeric Deutsch and Jonathan Vos Post, Apr 29 2006