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A220885 a(3)=5, a(4)=8, a(5)=12; thereafter a(n) = a(n-1) + A000931(n+7). 1
5, 8, 12, 19, 28, 40, 56, 77, 105, 142, 191, 256, 342, 456, 607, 807, 1072, 1423, 1888, 2504, 3320, 4401, 5833, 7730, 10243, 13572, 17982, 23824, 31563, 41815, 55396, 73387, 97220, 128792, 170616, 226021, 299417, 396646, 525447, 696072, 922102, 1221528, 1618183, 2143639, 2839720, 3761831, 4983368 (list; graph; refs; listen; history; text; internal format)
OFFSET
3,1
LINKS
P. Caron, J.-M. Champarnaud and L. Mignot, Multi-tilde-bar expressions and their automata, Acta Informatica, September 2012, Volume 49, Issue 6, pp 413-436. DOI 10.1007/s00236-012-0167-x. See the sequence t(k).
FORMULA
a(3)=5, a(4)=8, a(5)=12; thereafter a(n) = a(n-1) + Pad(n) + 2*Pad(n+1) + 2*Pad(n+2), where Pad() = A000931().
a(n) = a(n-1)+a(n-2)-a(n-4) for n>8. G.f.: x^3*(x^5+2*x^4-x^3-x^2+3*x+5) / ((x-1)*(x^3+x^2-1)). [Colin Barker, Jan 04 2013]
a(n) = a(n-1) + A000931(n+7) for n > 5. - Reinhard Zumkeller, Feb 19 2013
a(n) = a(n-2) + a(n-3) + 9 for n >= 8. - Greg Dresden, May 18 2020
MATHEMATICA
Join[{5, 8}, LinearRecurrence[{1, 1, 0, -1}, {12, 19, 28, 40}, 50]] (* Harvey P. Dale, May 30 2014 *)
PROG
(Haskell)
a220885 n = a220885_list !! (n-3)
a220885_list = 5 : 8 : zs where
zs = 12 : zipWith (+) zs (drop 13 a000931_list)
-- Reinhard Zumkeller, Feb 19 2013
CROSSREFS
Sequence in context: A314414 A314415 A314416 * A314417 A314418 A322033
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Dec 29 2012, based on an email from Ludovic Mignot, Dec 27 2012
EXTENSIONS
Simpler definition from Reinhard Zumkeller, Dec 30 2012
STATUS
approved

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Last modified April 25 03:15 EDT 2024. Contains 371964 sequences. (Running on oeis4.)