A078423 - OEIS

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

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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