A078423 Group the natural numbers into clumps with increasing prime numbers of elements, then multiply the members of each clump.

2, 60, 30240, 98017920, 857180548224000, 109720581991308288000, 70265584374661732509573120000, 61765285634580106110458762035200000, 642817384174195049892129048242945261568000000

Offset

1,1

Links

Table of n, a(n) for n=1..9.

Formula

a(n) = A007504(n)!/A007504(n-1)!. - Andrew Howroyd, Oct 16 2023

Example

Dividing 1,2,3,4,5,6,7,8,9,10,... into clumps of 2,3,5,.. elements: {1,2}, {3,4,5}, {6,7,8,9,10}, ... and then multiply each clumps to get 2,60,30240,...

Crossrefs

Cf. A007504, A034956.

Sequence in context: A173221 A375840 A082787 * A231024 A356584 A121493

Adjacent sequences: A078420 A078421 A078422 * A078424 A078425 A078426

Keyword

nonn

Author

Lior Manor, Dec 29 2002

Status

approved