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A075088
Smallest triangular number with n prime factors (counted with multiplicity).
10
1, 3, 6, 28, 36, 120, 528, 2080, 2016, 25200, 32640, 819840, 131328, 7874496, 20476800, 52433920, 8386560, 102767616, 536887296, 2147450880, 26306560000, 16240435200, 116802736128, 34359607296, 2199022206976, 549755289600
OFFSET
0,2
LINKS
EXAMPLE
a(3)=28 because 28 is a triangular number with 3 prime factors: 28 = 2*2*7.
PROG
(PARI) a(n)=if(n<0, 0, s=1; while(abs(bigomega(s*(s+1)/2)-n)>0, s++); s*(s+1)/2)
CROSSREFS
Sequence in context: A083675 A085076 A076711 * A102428 A128056 A068808
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Sep 13 2002
EXTENSIONS
More terms from Benoit Cloitre, Sep 17 2002
a(21)-a(24) from Mohammed Bouayoun (bouyao(AT)wanadoo.fr), Mar 15 2004
Edited by Ray Chandler, Dec 17 2004
a(25) from Ray Chandler, Dec 22 2004
STATUS
approved