A344889 Divide the positive integers into subsets of lengths given by successive primes. a(n) is the product of primes contained in the n-th subset.

2, 15, 7, 2431, 437, 1363783, 107113, 1249792339, 56606581, 1741209542339, 8811899415119, 1107997261359193637, 113411646442333, 5544791201146623008917, 785518504414223, 88816991126218293876923, 140194949408966090156937953, 517859057576547860552412883, 6474009927400912083137

Offset

1,1

Links

Table of n, a(n) for n=1..19.

Example

a(1) = 2 because the first subset is [1,2] (length = 2) and the product of primes contained in it is 2.
a(2) = 15 because the second subset is [3,4,5] (length = 3) and the product of primes contained in it is 3 * 5 = 15.
a(3) = 7 because the third subset is [6,7,8,9,10] (length = 5) and the product of primes contained in it is 7.
a(4) = 2431 because the fourth subset is [11,12,13,14,15,16,17] (length = 7) and the product of primes contained in it is 11 * 13 * 17 = 2431.

Mathematica

nterms=100; list = TakeList[Range[Sum[Prime[i], {i, nterms}]], Prime[Range[nterms]]]; listprime=Map[Select[#, PrimeQ]&, list]; Map[Apply[Times, #]&, listprime]

Crossrefs

Cf. A000040, A002110, A344718.

Sequence in context: A128759 A066582 A111329 * A059445 A077518 A196242

Adjacent sequences: A344886 A344887 A344888 * A344890 A344891 A344892

Keyword

nonn

Author

Paolo Xausa, Jun 01 2021

Status

approved