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A074793
Sum of prime powers less than or equal to n.
2
0, 2, 5, 9, 14, 14, 21, 29, 38, 38, 49, 49, 62, 62, 62, 78, 95, 95, 114, 114, 114, 114, 137, 137, 162, 162, 189, 189, 218, 218, 249, 281, 281, 281, 281, 281, 318, 318, 318, 318, 359, 359, 402, 402, 402, 402, 449, 449, 498, 498, 498, 498, 551, 551, 551, 551, 551
OFFSET
1,2
LINKS
FORMULA
Is a(n) asymptotic to c*n^2/log(n) with c=0.55...?
From Daniel Suteu, Aug 20 2023: (Start)
a(n) = Sum_{k=1..floor(log_2(n))} Sum_{p prime <= n^(1/k)} p^k.
a(n) = A034387(n) + A081738(A000196(n)) + Sum_{p prime <= n^(1/3)} ((p^(floor(log_p(n))+1) - 1)/(p-1) - p^2 - p - 1). (End)
EXAMPLE
a(10)=38 because 2,3,4,5,7,8,9 are the prime powers less than or equal to 10 and 2+3+4+5+7+8+9 = 38.
MATHEMATICA
Accumulate[Table[If[PrimePowerQ[n], n, 0], {n, 60}]] (* Harvey P. Dale, Oct 04 2019 *)
PROG
(PARI) a(n)=sum(k=1, n, k*if(omega(k)-1, 0, 1))
CROSSREFS
KEYWORD
nonn
AUTHOR
Benoit Cloitre, Sep 07 2002
STATUS
approved