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.

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.

Links

Table of n, a(n) for n=1..73.

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

Cf. A000035, A173012, A173013, A173015, A173016.

Sequence in context: A339675 A095877 A024476 * A322017 A093087 A130893

Adjacent sequences: A173011 A173012 A173013 * A173015 A173016 A173017

Keyword

nonn,easy

Author

Jaroslav Krizek, Nov 06 2010

Status

approved