OFFSET
0,3
MATHEMATICA
Table[Sum[Sum[Prime[j]*EulerPhi[k - j], {j, 1, k - 1}] * DivisorSigma[1, n - k], {k, 1, n - 1}], {n, 1, 50}] (* Vaclav Kotesovec, Apr 12 2019 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Jon Perry, Jul 29 2003
EXTENSIONS
Name and offset corrected and more terms added by Ilya Gutkovskiy, Apr 12 2019
STATUS
approved