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A338302
a(n) is the first k such that n = Omega(k) = Omega(k-1) + Omega(k+1), or 0 if there is no such k, where Omega is A001222.
0
2, 4, 8, 56, 80, 624, 1216, 8576, 66176, 59049, 386560, 1476225, 7354880, 58989951, 70184960, 36315136, 8044724224, 39790739456, 53730279424, 96467701761, 2558408523776, 4857090670593, 24607835029504, 177629755867136
OFFSET
1,1
COMMENTS
a(25) <= 1485324488278016, a(26) <= 3203995725725697. - Daniel Suteu, Mar 28 2021
EXAMPLE
a(3) = 8 because Omega(7)=1, Omega(8)=3, Omega(9)=2 and 1+2=3.
MAPLE
wp:= 1: w:= 0:
for i from 2 do
wm:= w; w:= wp; wp:= numtheory:-bigomega(i+1);
if not assigned(A[w]) and w = wm+wp then
A[w]:= i;
if w = 12 then break fi;
fi
od:
seq(A[i], i=1..12);
CROSSREFS
Cf. A001222.
Sequence in context: A058816 A018446 A289324 * A359877 A068620 A073953
KEYWORD
nonn,more
AUTHOR
J. M. Bergot and Robert Israel, Oct 21 2020
EXTENSIONS
a(13)-a(16) from Hugo Pfoertner, Oct 21 2020
a(17)-a(19) from Daniel Suteu, Oct 22 2020
a(20)-a(24) from Daniel Suteu, Mar 28 2021
STATUS
approved