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A120110 Diagonal sums of number triangle A120108. 1
1, 2, 7, 15, 67, 92, 461, 1065, 3016, 3956, 29478, 42231, 379107, 547556, 603421, 991923, 12709228, 18540622, 241033695, 352271227, 389226278, 407797820, 5532937710, 8097345425, 30368363481, 41503874738, 98701094676, 127342427241 (list; graph; refs; listen; history; internal format)
OFFSET

0,2

FORMULA

a(n)=sum{k=0..floor(n/2), lcm(1,..,n-k+1)/lcm(1,..,k+1)}

CROSSREFS

Sequence in context: A200862 A096690 A050612 * A047694 A129666 A135781

Adjacent sequences:  A120107 A120108 A120109 * A120111 A120112 A120113

KEYWORD

easy,nonn

AUTHOR

Paul Barry (pbarry(AT)wit.ie), Jun 09 2006

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Last modified February 14 22:37 EST 2012. Contains 205679 sequences.