OFFSET
1,2
COMMENTS
0 5 10 15 20 25 30 35 40 45 ... a(n)=5n
1 6 11 16 21 26 31 36 41 46 ... a(n)=5n+1
2 7 12 17 22 27 32 37 42 47 ... a(n)=5n+2
3 8 13 18 23 28 33 38 43 48 ... a(n)=5n+3
4 9 14 19 24 29 34 39 44 49 ... a(n)=5n+4
REFERENCES
M. Cerasoli, F. Eugeni and M. Protasi, Elementi di Matematica Discreta, Bologna 1988
Emanuele Munarini and Norma Zagaglia Salvi, Matematica Discreta,UTET, CittaStudiEdizioni, Milano 1997
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
FORMULA
Starting with term a(10): a(n+5k) = a(n) + 5k, with k>=1.
G.f.: x*(5-4*x+9*x^2-4*x^3-4*x^4+8*x^5-13*x^7+21*x^9-17*x^10+4*x^14)/(1-x-x^5+x^6). - Robert Israel, Mar 23 2017
MAPLE
0, 5, 1, 10, 6, 2, 15, 11, 7, 3, seq(seq(t + 5*k, t=[15, 11, 7, 3, -1]), k=1..20); # Robert Israel, Mar 23 2017
MATHEMATICA
Select[Join[{0}, Table[Most[NestList[#-4&, 5n, 5]], {n, 20}]]//Flatten, #>=0&] (* Harvey P. Dale, Nov 26 2016 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Giovanni Teofilatto, Mar 16 2006
STATUS
approved