A366167 Semiprimes that are the sum of two successive terms of A092192.

25, 146, 201, 221, 249, 302, 365, 529, 662, 681, 849, 949, 1211, 1282, 1318, 1343, 1849, 2517, 3223, 3398, 3466, 3635, 3867, 3949, 4063, 4749, 4819, 4997, 5158, 6049, 6614, 7023, 7041, 7066, 7117, 7921, 8314, 8471, 8709, 8727, 8914, 8981, 9155, 9235, 9299, 9563, 10741, 10895, 10958, 11435, 11962

Offset

1,1

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Example

a(3) = 201 is a term because 201 = 95 + 106 = A092192(7) + A092192(8).

Maple

SP:= select(t -> numtheory:-bigomega(t) = 2, [$1..10000]):
A092192:= select(t -> numtheory:-bigomega(t) = 2, SP[2..-1]+SP[1..-2]):
select(t -> numtheory:-bigomega(t) = 2, A092192[2..-1]+A092192[1..-2]);

Mathematica

sim = Select[Range[4, 100000], 2 == PrimeOmega[#]; &]; se = Select[Drop[sim, 1]
+ Drop[sim, -1], 2 == PrimeOmega[#] &];    Select[Drop[se, 1] + Drop[se, -1], 2
== PrimeOmega[#] &]

Prog

(PARI) upto(n) = {my(pr = 10, res = List(), semiprimes = List([4, 6])); forfactored(i = 9, n, if(bigomega(i[2]) == 2, listpop(semiprimes, 1); listput(semiprimes, i[1]); s = semiprimes[1] + semiprimes[2]; if(bigomega(s) == 2, c = s + pr; if(c > n, return(res)); if(bigomega(c) == 2, listput(res, c)); pr = s))); res} \\ David A. Corneth, Oct 02 2023

Crossrefs

Cf. A001358, A092192.

Sequence in context: A193438 A139152 A123014 * A095971 A147421 A147083

Adjacent sequences: A366164 A366165 A366166 * A366168 A366169 A366170

Keyword

nonn

Author

Zak Seidov and Robert Israel, Oct 02 2023

Status

approved