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A366167 Semiprimes that are the sum of two successive terms of A092192. 2
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 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
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
Sequence in context: A193438 A139152 A123014 * A095971 A147421 A147083
KEYWORD
nonn
AUTHOR
Zak Seidov and Robert Israel, Oct 02 2023
STATUS
approved

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Last modified May 23 02:40 EDT 2024. Contains 372758 sequences. (Running on oeis4.)