A173470 Semiprimes in A023037.

85, 781, 137257, 28531167061

Offset

1,1

Comments

The terms a(5) etc. have at least 63 digits (if they exist), so the pattern of terms does not continue as in A001039. [From R. J. Mathar, Feb 27 2010]

Links

Table of n, a(n) for n=1..4.

Mathematica

f1[n_]:=Module[{s=0}, Do[s+=n^a, {a, 0, n-1}]; s]; f2[n_]:=Last/@FactorInteger[n]=={1, 1}||Last/@FactorInteger[n]=={2}; Select[Table[f1[n], {n, 50}], f2[ # ]&]

Crossrefs

Sequence in context: A339870 A183777 A297599 * A202009 A194533 A069308

Adjacent sequences: A173467 A173468 A173469 * A173471 A173472 A173473

Keyword

nonn

Author

Vladimir Joseph Stephan Orlovsky, Feb 19 2010

Status

approved