login
A187891
a(0)=0, a(1)=5, a(n)=a(n-1)+a(n-2)-1.
1
0, 5, 4, 8, 11, 18, 28, 45, 72, 116, 187, 302, 488, 789, 1276, 2064, 3339, 5402, 8740, 14141, 22880, 37020, 59899, 96918, 156816, 253733, 410548, 664280, 1074827, 1739106, 2813932, 4553037, 7366968, 11920004, 19286971, 31206974, 50493944, 81700917
OFFSET
0,2
FORMULA
a(n) = 1+A022120(n-2), n>2. - R. J. Mathar, Mar 15 2011
G.f.: -x^2*(-5+6*x) / ( (x-1)*(x^2+x-1) ). - R. J. Mathar, Mar 15 2011
MATHEMATICA
Join[{a=0, b=5}, Table[c=a+b-1; a=b; b=c, {n, 100}]]
nxt[{a_, b_}]:={b, a+b-1}; NestList[nxt, {0, 5}, 40][[All, 1]] (* Harvey P. Dale, Nov 03 2022 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved