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A173014
a(1) = 1, for n >= 2; a(n) = the smallest number h such that sigma(h) = A000203(h) = a(n-1) + 4, a(n) = 0 if no such number exists.
4
1, 0, 3, 4, 7, 0, 3, 4, 7, 0, 3, 4, 7, 0, 3, 4, 7, 0, 3, 4, 7, 0, 3, 4, 7, 0, 3, 4, 7, 0, 3, 4, 7, 0, 3, 4, 7, 0, 3, 4, 7, 0, 3, 4, 7, 0, 3, 4, 7, 0, 3, 4, 7, 0, 3, 4, 7, 0, 3, 4, 7, 0, 3, 4, 7, 0, 3, 4, 7, 0, 3, 4, 7
OFFSET
1,3
COMMENTS
a(1) = 1, a(n) = periodic sequence with period (0, 3, 4, 7) for n >= 2.
FORMULA
A000203(a(n)) = a(n-1) + 4 for n >= 2.
MATHEMATICA
PadRight[{1}, 80, {7, 0, 3, 4}] (* Harvey P. Dale, May 09 2012 *)
PROG
(PARI) a(n)=if(n>1, [4, 7, 0, 3][n%4+1], 1) \\ Charles R Greathouse IV, Feb 19 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Jaroslav Krizek, Nov 06 2010
STATUS
approved