OFFSET
1,3
COMMENTS
For n >= 2, it appears that m is the least prime >= n*(n+1)/2, and row n consists of
1,2,3,...,n-1 and m - n*(n-1)/2. Robert Israel, Dec 22 2024
LINKS
Robert Israel, Table of n, a(n) for n = 1..7260 (first 120 rows, flattened)
EXAMPLE
Triangle begins:
1;
1,2;
1,2,4;
1,2,3,5;
1,2,3,4,7;
1,2,3,4,5,8;
MAPLE
g:= proc(S, m, n) # lex-first sublist of sorted list S of size n with sum m, or FAIL
option remember;
local nS, i, v;
nS:= nops(S);
if nS < n or convert(S[1..n], `+`) > m or convert(S[-n .. -1], `+`) < m then return FAIL fi;
if n = 0 then if m = 0 then return [] else return FAIL fi fi;
for i from 1 to nS while S[i] <= m do
v:= procname(S[i+1..-1], m-S[i], n-1);
if v <> FAIL then return [S[i], op(v)] fi
od;
FAIL
end proc:
f:= proc(n) local m, v;
for m from 1 do
v:= g(select(t -> igcd(t, m) = 1, [$1..m]), m, n);
if v <> FAIL then return op(v) fi
od
end proc:
for n from 1 to 20 do f(n) od; # Robert Israel, Dec 22 2024
PROG
(PARI) row(n) = {my(m=n*(n-1)/2, v); for(k=m+n, oo, v=List([1]); for(i=2, k-m, if(gcd(k, i)==1, listput(v, i))); if(#v>=n, forsubset([#v, n], w, if(sum(i=1, n, v[w[i]])==k, return(vector(n, i, v[w[i]])))))); } \\ Jinyuan Wang, May 23 2020
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Amarnath Murthy, Mar 27 2003
EXTENSIONS
More terms from R. J. Mathar, Mar 23 2007
More terms from Jinyuan Wang, May 23 2020
STATUS
approved