login
A183140
a(n) = [1/s]+[2/s]+...+[n/s], where s=2+sqrt(2) and []=floor.
3
0, 0, 0, 1, 2, 3, 5, 7, 9, 11, 14, 17, 20, 24, 28, 32, 36, 41, 46, 51, 57, 63, 69, 76, 83, 90, 97, 105, 113, 121, 130, 139, 148, 157, 167, 177, 187, 198, 209, 220, 232, 244, 256, 268, 281, 294, 307, 321, 335, 349, 363, 378, 393, 408
OFFSET
0,5
COMMENTS
A183139(n) + a(n) = A000217(n) (the triangular numbers).
LINKS
FORMULA
a(n) = [1/s]+[2/s]+...+[n/s], where s=2+sqrt(2) and []=floor.
MATHEMATICA
Accumulate[Floor[Range[60]/(2+Sqrt[2])]] (* Harvey P. Dale, Oct 20 2017 *)
PROG
(PARI) default(realprecision, 100); s=2+sqrt(2); for(n=1, 99, print1(sum(k=1, n, floor(k/s)), ", "))
CROSSREFS
Sequence in context: A065130 A023535 A056834 * A286283 A139282 A375985
KEYWORD
nonn
AUTHOR
Clark Kimberling, Dec 26 2010
STATUS
approved