The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A047055 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A047055

Quintuple factorial numbers: a(n) = Product_{k=0..n-1} (5*k + 2).
(history; published version)

#49 by Michel Marcus at Mon Dec 19 03:44:42 EST 2022

STATUS

reviewed

approved

#48 by Joerg Arndt at Mon Dec 19 01:52:31 EST 2022

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proposed

reviewed

#47 by Joerg Arndt at Mon Dec 19 01:52:28 EST 2022

STATUS

editing

proposed

#46 by Joerg Arndt at Mon Dec 19 01:52:25 EST 2022

FORMULA

Let b(n) = b(n-1) + 5; then a(n) = b(n)*a(n-1). - Roger L. Bagula, Sep 17 2008

MATHEMATICA

k=5; b[1]=2; b[n_]:= b[n] = b[n-1] +k; a[0]=1; a[1]=2; a[n_]:= a[n]= a[n-1]*b[n]; Table[a[n], {n, 0, 20}] (* Roger L. Bagula, Sep 17 2008 *)

STATUS

reviewed

editing

#45 by Joerg Arndt at Mon Dec 19 01:51:07 EST 2022

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proposed

reviewed

#44 by Amiram Eldar at Mon Dec 19 01:18:09 EST 2022

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editing

proposed

#43 by Amiram Eldar at Mon Dec 19 00:49:04 EST 2022

DATA

1, 2, 14, 168, 2856, 62832, 1696464, 54286848, 2008613376, 84361761792, 3965002804224, 206180145819648, 11752268311719936, 728640635326636032, 48818922566884614144, 3514962424815692218368, 270652106710808300814336, 22193472750286280666775552

#42 by Amiram Eldar at Mon Dec 19 00:46:17 EST 2022

CROSSREFS

Cf. A052562, A008548, A047056, A169621.

#41 by Amiram Eldar at Mon Dec 19 00:45:52 EST 2022

FORMULA

Sum_{n>=0} 1/a(n) = 1 + (e/5^3)^(1/5)*(Gamma(2/5) - Gamma(2/5, 1/5)). - Amiram Eldar, Dec 19 2022

STATUS

approved

editing

#40 by Alois P. Heinz at Sat Aug 27 18:40:11 EDT 2022

STATUS

proposed

approved