|
Search: id:A065435
|
|
|
| A065435 |
|
a(3) = 2, a(4) = 3; for n > 5, a(n) = {a(n-2)}+{a(n-1)}, where {a} means largest prime <= a. |
|
+0
2
|
|
| 2, 3, 5, 8, 12, 18, 28, 40, 60, 96, 148, 228, 366, 586, 936, 1506, 2428, 3922, 6342, 10256, 16590, 26826, 43394, 70212, 113598, 183798, 297388, 481174, 778548, 1259712, 2038242, 3297918, 5336130, 8634042, 13970112, 22604076, 36574162
(list; graph; listen)
|
|
|
OFFSET
|
3,1
|
|
|
FORMULA
|
a(n) = A007917(a(n-2)) + A007917(a(n-1)). - Jonathan Vos Post (jvospost3(AT)gmail.com), Jul 10 2008
|
|
EXAMPLE
|
a(9) = 28 because 11+17 = 28 and 11 largest prime <= a(7) = 12 and 17 is largest prime <= a(8) = 18
|
|
MATHEMATICA
|
PrevPrim[n_] := Block[ {k = n}, While[ !PrimeQ[k], k-- ]; Return[k]]; a[3] = 2; a[4] = 3; a[n_] := a[n] = PrevPrim[ a[n - 1]] + PrevPrim[ a[n - 2]]; Table[ a[n], {n, 3, 45} ]
|
|
CROSSREFS
|
Cf. A055500, A000045.
Cf. A000040, A000045, A007917, A055500.
Adjacent sequences: A065432 A065433 A065434 this_sequence A065436 A065437 A065438
Sequence in context: A061419 A130732 A018135 this_sequence A055804 A124062 A099823
|
|
KEYWORD
|
nonn,easy,nice
|
|
AUTHOR
|
Bodo Zinser (BodoZinser(AT)Compuserve.com), Nov 17 2001
|
|
EXTENSIONS
|
More terms from Robert G. Wilson v (rgwv(AT)rgwv.com), Nov 19 2001
|
|
|
Search completed in 0.002 seconds
|
