A103520 - OEIS

A103520

a(1) = 1, a(n) = product of n successive numbers starting with a(n-1) + 1.

1, 6, 504, 65813284680, 1234718152224069224489356305213161520251951242625962440

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OFFSET

1,2

COMMENTS

a(6) has 325 digits and a(7) has 2272 digits. - Harvey P. Dale, Aug 23 2014

LINKS

FORMULA

a(n+1) = !{a(n)+n +1}/!{a(n)}

EXAMPLE

a(2) = 2*3 = 6, a(3) = 7*8*9 = 504.

MATHEMATICA

nxt[{n_, a_}]:={n+1, Times@@Range[a+1, a+1+n]}; Transpose[NestList[nxt, {1, 1}, 5]][[2]] (* Harvey P. Dale, Aug 23 2014 *)

CROSSREFS

KEYWORD

easy,nonn

AUTHOR

EXTENSIONS

More terms from Olaf Voß, Feb 26 2005. (The next term is too large to include.)

STATUS

approved