login
A323085
Semiprimes that are the sum of the first k terms of A092190 for some k.
1
4, 14, 8567, 16499, 151211, 344891, 418831, 585197, 1049882, 1186582, 1671029, 2503966, 2989387, 4802311, 8291795, 9769711, 11420129, 13279957, 13677063, 15356513, 16258813, 24318863, 26874293, 39317497, 42862751
OFFSET
1,1
COMMENTS
If we call the semiprime numbers A001358 level 1, and A092190 level 2, then this sequence is level 3.
LINKS
Wilmer Emiro Castrillon Calderon, Table of n, a(n) for n = 1..100
EXAMPLE
a(2) = 14 = Sum_{i=1..2} A092190(i).
a(3) = 8567 = Sum_{i=1..13} A092190(i).
MATHEMATICA
f[w_] := Select[Most@ NestWhile[Append[#1, {#2, #2 + #1[[-1, -1]]}] & @@ {#, w[[Length@ # + 1]]} &, {{#, #}} &@ First[w], #[[-1, -1]] <= Max@ w &][[All, -1]], PrimeOmega@ # == 2 &]; Block[{s = Select[Range[10^6], PrimeOmega@ # == 2 &], t}, f@ f@ s] (* Michael De Vlieger, Jan 04 2019 *)
PROG
(C++) typedef unsigned long long int ulli;
void Level3(){ vector<ulli>::iterator low; ulli acum = 0;
for(int i = 0; i < level2.size(); i++){
acum += level2[i];
low=lower_bound (semiprimes.begin(), semiprimes.end(), acum);
if(semiprimes[low - semiprimes.begin()] == acum){
printf("%llu\n", acum);
} } } //where level2 is a vector with A092190.
CROSSREFS
Sequence in context: A022508 A161741 A186509 * A097548 A218047 A344938
KEYWORD
nonn
AUTHOR
STATUS
approved