OFFSET
1,3
COMMENTS
The natural numbers preceded by 0 constitute the first column; the other columns are built by a slight modification of the definition of Recamán's sequence. E.g., the second column is Recamán's sequence deprived of its first term 0 (cf. A005132).
LINKS
Klaus Brockhaus, Table of n, a(n) for n = 1..1000
EXAMPLE
Upper left triangle of the array is
0 1 3 9 2 18 15 69 228...
1 3 9 2 18 15 69 228...
2 6 7 16 3 54 159 ...
3 2 14 15 39 90 ...
4 7 1 36 36 ...
5 13 21 3 ...
6 20 33 ...
7 12 ...
8 ...
PROG
(PARI) {m=40; A=matrix(m, m); k=1; for(j=1, m, A[j, k]=j-1); print1(A[1, k], ", "); for(k=2, m, print1(A[1, k]=A[2, k-1], ", "); s=Set(A[1, k]); for(j=2, m-k+1, e=A[j-1, k]-A[j+1, k-1]; if((e>0)&&!setsearch(s, e), A[j, k]=e, A[j, k]=A[j-1, k]+A[j+1, k-1]); s=setunion(s, Set(A[j, k]))))} \\ Klaus Brockhaus, Aug 05 2008
CROSSREFS
KEYWORD
nonn
AUTHOR
Philippe Lallouet (philip.lallouet(AT)orange.fr), Jul 28 2008
EXTENSIONS
Edited and extended by Klaus Brockhaus, Aug 05 2008
STATUS
approved