The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A066120 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A066120

Superduperprimorials: product of first n terms in Chernoff sequence.
(history; published version)

#18 by Susanna Cuyler at Sat Jun 16 18:36:33 EDT 2018

STATUS

reviewed

approved

#17 by Joerg Arndt at Sat Jun 16 02:29:22 EDT 2018

STATUS

proposed

reviewed

#16 by Jon E. Schoenfield at Fri Jun 15 21:41:08 EDT 2018

STATUS

editing

proposed

#15 by Jon E. Schoenfield at Fri Jun 15 21:41:06 EDT 2018

COMMENTS

First number with n distinct positive triangular exponents in its prime factorization. Subsequence of A025487. [From _- _Matthew Vandermast_, Nov 05 2009; edited May 23 2012]

LINKS

Harry J. Smith, <a href="/A066120/b066120.txt">Table of n, a(n) for n = 0,...,17</a>

FORMULA

a(n) = Product_{1< = i< = 1..n}[ prime(i)^((n-i+1)*(n-i+2)/2)] = a(n-1)*A006939(n) = A066119(n-3, 4).

EXAMPLE

a(4) = 2*(2*(2*3))*(2*(2*3)*(2*3*5)) = 2*(2*6)*(2*6*30) = 2*12*360 = 8640.

PROG

(PARI) { for (n=0, 17, a=1; for(i=1, n, a*=prime(i)^((n - i + 1)*(n - i + 2)/2)); write("b066120.txt", n, " ", a) ) } [From _\\ _Harry J. Smith_, Feb 01 2010]

STATUS

approved

editing

#14 by Joerg Arndt at Fri Feb 21 11:50:20 EST 2014

STATUS

proposed

approved

#13 by Arkadiusz Wesolowski at Fri Feb 21 11:28:47 EST 2014

STATUS

editing

proposed

#12 by Arkadiusz Wesolowski at Fri Feb 21 11:28:43 EST 2014

KEYWORD

nonn,easy

STATUS

approved

editing

#11 by T. D. Noe at Thu May 24 11:41:13 EDT 2012

STATUS

proposed

approved

#10 by Matthew Vandermast at Wed May 23 23:31:39 EDT 2012

STATUS

editing

proposed

#9 by Matthew Vandermast at Wed May 23 23:29:24 EDT 2012

COMMENTS

First number with n distinct positive triangular exponents in its prime factorization. Subsequence of A025487. [From Matthew Vandermast, Nov 05 2009; edited May 23 2012]

CROSSREFS

Cf. A000040, A002110, A006939, A055462, A166475.

STATUS

approved

editing