A361262 Numbers k such that k+i^2, i=0..6 are all semiprimes.

3238, 4162, 4537, 13918, 16837, 17857, 18673, 24553, 55477, 62353, 78457, 84358, 92878, 102838, 106813, 129838, 135853, 140002, 142822, 146722, 148318, 151957, 166177, 180013, 184213, 187933, 194338, 210637, 214393, 231757, 242698, 271198, 274393, 305677

Offset: 1

Author

Alexandru Petrescu, Mar 06 2023

Keywords

• nonn

Examples

			3238 is a term because 3238=2*1619; 3239=41*79; 3242=2*1621; 3247=17*191; 3254=2*1627; 3263=13*251; 3274=2*1637.
		

Crossrefs

Subsequence of A070552.

Cf. A001358 (semiprimes).

Programs

Maple

q:= n-> andmap(x-> numtheory[bigomega](x)=2, [n+i^2$i=0..6]):
select(q, [$1..400000])[];  # Alois P. Heinz, Mar 06 2023

Mathematica

okQ[k_] := AllTrue[Table[k+i^2, {i, 0, 6}], PrimeOmega[#] == 2&];
Select[Range[400000], okQ] (* Jean-François Alcover, Feb 02 2025 *)

PARI

isok(k) = sum(i=0, 6, bigomega(k+i^2)==2) == 7;