The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A060301

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A060301

For n>3: a(n) is a multiple of three distinct earlier terms.
(history; published version)

#6 by Alois P. Heinz at Thu Nov 16 16:28:18 EST 2017

STATUS

editing

approved

#5 by Alois P. Heinz at Thu Nov 16 16:28:13 EST 2017

EXAMPLE

a(15) = 10800 = 2*30*180 = a(1)*a(4)*a(5).

STATUS

proposed

editing

#4 by Rachel Barnett at Thu Nov 16 16:15:40 EST 2017

STATUS

editing

proposed

#3 by Rachel Barnett at Thu Nov 16 16:15:37 EST 2017

LINKS

R. G. Wilson, V, <a href="/A007335/a007335.pdf">Note, n.d.</a>

STATUS

approved

editing

#2 by Russ Cox at Fri Mar 30 18:51:33 EDT 2012

AUTHOR

_Henry Bottomley (se16(AT)btinternet.com), _, Mar 28 2001

Discussion

Fri Mar 30

18:51

OEIS Server: https://oeis.org/edit/global/247

#1 by N. J. A. Sloane at Fri May 16 03:00:00 EDT 2003

NAME

For n>3: a(n) is a multiple of three distinct earlier terms.

DATA

2, 3, 5, 30, 180, 300, 450, 1080, 1800, 2700, 3000, 4500, 6480, 6750, 10800, 16200, 18000, 27000, 30000, 38880, 40500, 45000, 64800, 67500, 97200, 101250, 108000, 162000, 180000, 233280, 243000, 270000, 300000, 388800, 405000, 450000, 583200

OFFSET

1,1

FORMULA

a(n) is of the form 2^b*3^c*5^d where either b+c+d=1, or where each of b, c and d are positive and the largest of the three is an odd number less than the sum of the other two. For n>3: a(n) is 30 times a power of 6 times a power of 10 times a power of 15.

EXAMPLE

a(15)=10800=2*30*180=a(1)*a(4)*a(5)

CROSSREFS

Cf. A000423.

KEYWORD

nonn

AUTHOR

Henry Bottomley (se16(AT)btinternet.com), Mar 28 2001

STATUS

approved