OFFSET
1,1
COMMENTS
EXAMPLE
The sequence of terms together with their prime indices begins:
5: {3}
9: {2,2}
14: {1,4}
15: {2,3}
44: {1,1,5}
45: {2,2,3}
50: {1,3,3}
78: {1,2,6}
104: {1,1,1,6}
105: {2,3,4}
110: {1,3,5}
135: {2,2,2,3}
196: {1,1,4,4}
225: {2,2,3,3}
272: {1,1,1,1,7}
276: {1,1,2,9}
342: {1,2,2,8}
380: {1,1,3,8}
405: {2,2,2,2,3}
476: {1,1,4,7}
MATHEMATICA
Select[Range[1000], DivisorSigma[0, #]==Total[Cases[FactorInteger[#], {p_, k_}:>PrimePi[p]*k]]-1&]
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, May 23 2019
STATUS
approved