OFFSET
0,2
LINKS
Rémy Sigrist, Table of n, a(n) for n = 0..10000
FORMULA
EXAMPLE
a(0) = 1.
a(1) = a(0) + a(0) = 1 + 1 = 2.
a(2) = a(0) + a(1) = 1 + 2 = 3.
a(3) = a(1) + a(0) = 2 + 1 = 3.
a(4) = a(0) + a(2) = 1 + 3 = 4.
a(5) = a(1) + a(1) = 2 + 2 = 4.
a(6) = a(2) + a(0) = 3 + 1 = 4.
PROG
(PARI) a(n) = {if(n==0, return(1)); my(s = ceil((-3 + sqrt(8*n+1))/ 2), b = binomial(s+2, 2), k = b - n, m = s - k); a(k) + a(m)}
(PARI) a=vector(87); print1(a[u=1]=1); for (d=1, oo, for (n=1, d, print1(", "a[u++]=a[n]+a[d+1-n]); if (u==87, break (2)))) \\ Rémy Sigrist, Feb 12 2021
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
David A. Corneth, Aug 25 2017
STATUS
approved