OFFSET
1,1
COMMENTS
Triangle begins : {10} {-2, 3} {-4, 6, -10} {18, -27, 45, -63} {-10, 15, -25, 35, -55} {-22, 33, -55, 77, -121, 143} The idea was to find permutation function that gave small sums.
FORMULA
a(n) = if 10 Mod[Prime[n], 10] is 1 then -Prime[n]-6 if 3 then -Prime[n]-2 else if 7 then Prime[n]-2, if 9 then Prime[n]-6 a[1]=-5 a[3]=2 T(n, k)=a(k)*Prime[n]*(-1)^k aout[n]=Sum[T(n, k], {k, 1, n]
MATHEMATICA
a[n_] := -(Prime[n] + 6) /; 10 - Mod[Prime[n], 10] == 1; a[n_] := -(Prime[n] + 2) /; 10 - Mod[Prime[n], 10] == 3; a[n_] := Prime[n] - 2 /; (10 - Mod[Prime[n], 10] == 7); a[n_] := Prime[n] - 6 /; (10 - Mod[Prime[n], 10] == 9); a[1] = -Prime[3]; a[3] = Prime[1]; digits = 200 Table[Abs[Apply[Plus, Table[Prime[n]*a[m]*(-1)^n, {n, 1.m}]]], {m, 1, digits}]
CROSSREFS
KEYWORD
nonn,uned
AUTHOR
Roger L. Bagula, Apr 10 2005
STATUS
approved