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A071228 a(n) = n*(n-th composite number). 1
4, 12, 24, 36, 50, 72, 98, 120, 144, 180, 220, 252, 286, 336, 375, 416, 459, 504, 570, 640, 693, 748, 805, 864, 950, 1014, 1080, 1176, 1276, 1350, 1426, 1536, 1617, 1700, 1785, 1872, 1998, 2090, 2184, 2280, 2378, 2520, 2666, 2772, 2880, 2990, 3102 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Complement of A171521(n). [From Jaroslav Krizek, Dec 13 2009]

LINKS

Table of n, a(n) for n=1..47.

FORMULA

a(1)= 1*4, a(2)= 2*6, a(3)= 3*9, a(4) = 4*10

a(n) = A000027(n) * A002808(n) = n * A002808(n). [From Jaroslav Krizek, Dec 13 2009]

MAPLE

count := 1: for i from 2 to 100 do if isprime(i) then else printf(`%d, `, i*count); count := count+1 fi: od:

CROSSREFS

Sequence in context: A008077 A072389 A218391 * A108997 A159795 A033602

Adjacent sequences:  A071225 A071226 A071227 * A071229 A071230 A071231

KEYWORD

nonn

AUTHOR

Amarnath Murthy, May 17 2002

EXTENSIONS

More terms and Maple code from James A. Sellers, May 28, 2002

Edited by N. J. A. Sloane, Jul 02 2008 at the suggestion of R. J. Mathar

STATUS

approved

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Last modified September 19 15:54 EDT 2014. Contains 246977 sequences.