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A166475 4th level primorials: product of first n superduperprimorials. 7
1, 2, 48, 414720, 270888468480000, 30900096179361042923520000000000, 1848494880770448654906901042987600267878400000000000000000000 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
COMMENTS
Next term has 110 digits.
a(n) = first counting number with n distinct positive tetrahedral exponents in its prime factorization (cf. A000292).
Note: a(n) is not the first counting number with n distinct square exponents in its prime factorization, as previously stated. That sequence is A212170. - Matthew Vandermast, May 23 2012
LINKS
FORMULA
a(n) = Product_{k=1..n} prime(k)^((n-k+1)^2).
EXAMPLE
a(3) = 414720 = 2^10*3^4*5^1 has 3 positive tetrahedral exponents in its prime factorization (cf. A000292). It is the smallest number with this property.
CROSSREFS
Subsequence of A025487.
Cf. A002110, A006939, A066120 for first, second and third level primorials.
Sequence in context: A344665 A212170 A057527 * A152688 A046873 A261125
KEYWORD
nonn,easy
AUTHOR
Matthew Vandermast, Nov 05 2009
EXTENSIONS
Offset corrected by Matthew Vandermast, Nov 07 2009
Edited by Matthew Vandermast, Nov 10 2009, May 23 2012
Name changed by Arkadiusz Wesolowski, Feb 21 2014
STATUS
approved

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Last modified June 17 14:56 EDT 2024. Contains 373448 sequences. (Running on oeis4.)