

A120110


Diagonal sums of number triangle A120108.


2



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
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OFFSET

0,2


LINKS

Muniru A Asiru, Table of n, a(n) for n = 0..1000


FORMULA

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


PROG

(GAP) List([0..30], n>Sum([0..Int(n/2)], k>Lcm(List([1..nk+1], i>i))/Lcm(List([1..k+1], i>i)))); # Muniru A Asiru, Mar 04 2019
(PARI) a(n) = sum(k=0, n\2, lcm([1..nk+1])/lcm([1..k+1])); \\ Michel Marcus, Mar 04 2019


CROSSREFS

Cf. A120108.
Sequence in context: A279286 A282197 A050612 * A047694 A262016 A129666
Adjacent sequences: A120107 A120108 A120109 * A120111 A120112 A120113


KEYWORD

easy,nonn


AUTHOR

Paul Barry, Jun 09 2006


STATUS

approved



