OFFSET
1,4
COMMENTS
If q are proper divisors of n then values of sequence a(n) are the bending moments at point 0 of static forces of sizes sigma(q) operating in places q on the cantilever as the nonnegative number axis of length n with support at point 0 by the schema: a(n) = Sum_{q | n} q*sigma(q).
LINKS
Jaroslav Krizek, Table of n, a(n) for n = 1..1000
EXAMPLE
For n=21 with proper divisors [1,3,7] we have: a(21) = 7*sigma(7) + 3*sigma(3) + 1*sigma(1) = 7*8 + 3*4 + 1*1 = 69.
MATHEMATICA
a245484[n_Integer] := Total[#*DivisorSigma[1, #] & /@ Most[Divisors[n]]]; a245484 /@ Range[60] (* Michael De Vlieger, Aug 17 2014 *)
PROG
(Magma)[((&+[d*SumOfDivisors(d): d in Divisors(n)])-n*SumOfDivisors(n)): n in [1..1000]]
CROSSREFS
KEYWORD
nonn
AUTHOR
Jaroslav Krizek, Aug 16 2014
STATUS
approved