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A379530
a(n) = (A135318(3*n) + A135318(3*n+1) + A135318(3*n+2))/3.
0
1, 3, 8, 23, 64, 185, 512, 1479, 4096, 11833, 32768, 94663, 262144, 757305, 2097152, 6058439, 16777216, 48467513, 134217728, 387740103, 1073741824, 3101920825, 8589934592, 24815366599, 68719476736, 198522932793, 549755813888, 1588183462343, 4398046511104, 12705467698745
OFFSET
0,2
FORMULA
a(n) = 7*a(n-2) + 8*a(n-4) with a(0)=1, a(1)=3, a(2)=8, a(3)=23 for n >= 4.
a(2*n) = A001018(n).
a(2*n+1) = A015565(n+1) + A013730(n).
MATHEMATICA
LinearRecurrence[{0, 7, 0, 8}, {1, 3, 8, 23}, 30] (* Amiram Eldar, Dec 31 2024 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Paul Curtz, Dec 24 2024
STATUS
approved