A281824 Numbers that are the sum of 6 consecutive semiprimes.

58, 75, 91, 107, 123, 142, 161, 175, 191, 205, 225, 241, 258, 278, 297, 316, 332, 348, 366, 385, 405, 429, 452, 473, 491, 508, 524, 536, 546, 566, 590, 614, 639, 664, 690, 706, 718, 732, 747, 762, 782, 802, 822, 838, 851, 872, 889, 906, 924, 945, 968, 990

Offset

1,1

Comments

Semiprime analog of A127333. First terms that are also in A127333: 690, 990, 1172, 1250, 1286, 2288, 4798, 5064.

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Formula

a(n) ~ 6n log n/log log n. - Charles R Greathouse IV, Jan 31 2017

Mathematica

Total /@ Partition[Select[Range[4, 200], 2 == PrimeOmega[#] &], 6, 1]

Prog

(PARI) do(n)=my(v=List([58]), u=List(), t=58); forprime(p=2, n\2, forprime(q=2, min(p, n\p), listput(u, p*q))); u=Set(u); for(i=7, #u, listput(v, t+=u[i]-u[i-6])); Set(v) \\ Charles R Greathouse IV, Jan 31 2017

Crossrefs

Cf. A001358, A127333.

Sequence in context: A010338 A368615 A184074 * A127334 A275702 A306115

Adjacent sequences: A281821 A281822 A281823 * A281825 A281826 A281827

Keyword

nonn

Author

Zak Seidov, Jan 31 2017

Status

approved