OFFSET
1,2
COMMENTS
a(n+125) = a(n) + 210, n >= 7. Also maximal term difference is 4 = a(68)-a(67). - David W. Wilson, Jun 18 2001
LINKS
T. D. Noe, Table of n, a(n) for n=1..1000
Hsien-Kuei Hwang, Mihyun Kang, Guan-Huei Duh, Asymptotic Expansions for Sub-Critical Lagrangean Forms, LIPIcs Proceedings of Analysis of Algorithms 2018, Vol. 110. Schloss Dagstuhl-Leibniz-Zentrum für Informatik, 2018.
EXAMPLE
After 19, 22, 23 the next term is 25 as 24 has 2 as common divisor with 22.
MATHEMATICA
a[ 1 ]=1; a[ 2 ]=2; a[ 3 ]=3; a[ n_ ] := a[ n ]=Module[ {}, b=a[ n-1 ]; While[ GCD[ b, a[ n-1 ] ]>1||GCD[ b, a[ n-2 ] ]> 1||GCD[ b, a[ n-3 ] ]>1, b++ ]; b ] Array[ a, 100 ]
PROG
(PARI) { for (n=1, 1000, if (n>3, until (gcd(a, a1)==1 && gcd(a, a2)==1 && gcd(a, a3)==1, a++); a3=a2; a2=a1; a1=a, if (n==1, a=a3=1, if (n==2, a=a2=2, a=a1=3))); write("b062062.txt", n, " ", a) ) } \\ Harry J. Smith, Jul 31 2009
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Amarnath Murthy, Jun 12 2001
EXTENSIONS
More terms from Erich Friedman, Jun 15 2001
Clarified by Charles R Greathouse IV, Aug 02 2010
STATUS
approved