|
| |
|
|
A008851
|
|
Congruent to 0 or 1 mod 5.
|
|
31
|
|
|
|
0, 1, 5, 6, 10, 11, 15, 16, 20, 21, 25, 26, 30, 31, 35, 36, 40, 41, 45, 46, 50, 51, 55, 56, 60, 61, 65, 66, 70, 71, 75, 76, 80, 81, 85, 86, 90, 91, 95, 96, 100, 101, 105, 106, 110, 111, 115, 116, 120, 121, 125, 126, 130, 131, 135, 136, 140, 141, 145, 146, 150, 151
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
1,3
|
|
|
COMMENTS
|
n^2 and n have same last digit.
|
|
|
REFERENCES
|
Dickson, History of Theory of Numbers, I, p. 459.
|
|
|
LINKS
|
_Reinhard Zumkeller_, Table of n, a(n) for n = 1..10000
Index to sequences with linear recurrences with constant coefficients, signature (1,1,-1).
|
|
|
FORMULA
|
a(n) = 5*n-a(n-1)-4 (with a(0)=0) [From Vincenzo Librandi, Nov 18 2010]
G.f. x^2*(1+4*x) / ( (1+x)*(x-1)^2 ). - R. J. Mathar, Oct 07 2011
a(n+1)=Sum_k>=0 {A030308(n,k)*A146523(k)}. - From Philippe Deléham, Oct 17 2011.
a(n) = floor((5/3)*floor(3*n/2)). [Clark Kimberling, Jul 04 2012]
|
|
|
MAPLE
|
a[0]:=0:a[1]:=1:for n from 2 to 100 do a[n]:=a[n-2]+5 od: seq(a[n], n=0..61); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Mar 16 2008
|
|
|
MATHEMATICA
|
Select[Range[0, 151], MemberQ[{0, 1}, Mod[#, 5]] &] (* T. D. Noe, Mar 31 2013 *)
|
|
|
PROG
|
(Haskell)
a008851 n = a008851_list !! (n-1)
a008851_list = [10*n + m | n <- [0..], m <- [0, 1, 5, 6]]
-- Reinhard Zumkeller, Jul 27 2011
(PARI) a(n) = 5*(n\2)+bitand(n, 1); /* Joerg Arndt, Mar 31 2013 */
(PARI) a(n) = floor((5/3)*floor(3*n/2)); /* Joerg Arndt, Mar 31 2013 */
|
|
|
CROSSREFS
|
Cf. A003226, A045953, A046831, A046851, A086457.
Sequence in context: A074627 A067612 A064957 * A079259 A029772 A046827
Adjacent sequences: A008848 A008849 A008850 * A008852 A008853 A008854
|
|
|
KEYWORD
|
nonn,easy
|
|
|
AUTHOR
|
N. J. A. Sloane.
|
|
|
EXTENSIONS
|
Offset corrected by Reinhard Zumkeller, Jul 27 2011
|
|
|
STATUS
|
approved
|
| |
|
|
