OFFSET
0,2
MATHEMATICA
a[0] = 0; a[n_] := Which[m = Mod[n, 20]; m == 0, 10*n-100, m == 9, n+2, m == 10, n+10, m == 11, 10*n-20, MemberQ[ {2, 4, 6, 8, 13, 15, 17, 19}, m], 10*n-10, True, n+1]; Table[ a[n], {n, 0, 62}] (* Jean-François Alcover, Sep 24 2012 *)
CROSSREFS
KEYWORD
nice,nonn
AUTHOR
Henry Bottomley, Apr 27 2000
STATUS
approved