OFFSET
1,1
FORMULA
a(n) = A003056(n)+3, a(n) = A003057(n)+1; a(n) = t+3, where t=floor((-1+sqrt(8*n-7))/2). - Boris Putievskiy, May 07 2013
MATHEMATICA
Table[PadRight[{}, n, n+2], {n, 20}]//Flatten (* Harvey P. Dale, Sep 04 2019 *)
PROG
(Python)
from math import isqrt
def A133196(n): return 2+(isqrt(8*n)+1)//2 # Chai Wah Wu, Oct 17 2022
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul Curtz, Oct 09 2007
STATUS
approved