OFFSET
1,1
COMMENTS
Is a(n) nonzero for all n?
LINKS
Harry J. Smith, Table of n, a(n) for n = 1..1000
EXAMPLE
8^2 + (sigma(2 + 8) - sigma(2))^2 = 17^2 and k = 8 is the least natural number achieving this, so a(2) = 8.
PROG
(PARI) { for (n=1, 1000, s=sigma(n); k=0; b=0; while(b==0, k++; if (issquare(k^2 + (sigma(n+k) - s)^2), b=1)); write("b066790.txt", n, " ", k) ) } \\ Harry J. Smith, Mar 26 2010
CROSSREFS
KEYWORD
nonn
AUTHOR
Joseph L. Pe, Jan 18 2002
EXTENSIONS
Terms a(51) - a(72) from Harry J. Smith, Mar 26 2010
STATUS
approved