

A281258


Digital root of n*(n+1)*(n+2)/2.


2



0, 3, 3, 3, 6, 6, 6, 9, 9, 9, 3, 3, 3, 6, 6, 6, 9, 9, 9, 3, 3, 3, 6, 6, 6, 9, 9, 9, 3, 3, 3, 6, 6, 6, 9, 9, 9, 3, 3, 3, 6, 6, 6, 9, 9, 9, 3, 3, 3, 6, 6, 6, 9, 9, 9, 3, 3, 3, 6, 6, 6, 9, 9, 9, 3, 3, 3, 6, 6, 6, 9, 9, 9, 3, 3, 3, 6, 6, 6, 9, 9, 9, 3, 3, 3, 6, 6, 6, 9, 9, 9, 3, 3, 3, 6, 6, 6, 9, 9, 9, 3, 3, 3, 6, 6, 6, 9, 9, 9, 3, 3, 3, 6, 6, 6, 9, 9, 9
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OFFSET

0,2


COMMENTS

Also zero together with period 9: repeat [3, 3, 3, 6, 6, 6, 9, 9, 9].
Also the decimal expansion of 334001/1001001.


LINKS

Table of n, a(n) for n=0..117.
Index entries for linear recurrences with constant coefficients, signature (1,0,1,1,0,1,1).


FORMULA

a(n) = A010888(A027480(n)).
From Stefano Spezia, Aug 30 2022: (Start)
G.f.: 3*x*(1 + 2*x^3 + 3*x^6)/((1  x)*(1 + x^3 + x^6)).
a(n) = a(n1)  a(n3) + a(n4)  a(n6) + a(n7) for n > 7. (End)


MATHEMATICA

PadRight[{0}, 120, {9, 3, 3, 3, 6, 6, 6, 9, 9}] (* Harvey P. Dale, Mar 22 2018 *)


CROSSREFS

Cf. A010888, A027480.
Sequence in context: A073080 A171601 A057944 * A080607 A013322 A211534
Adjacent sequences: A281255 A281256 A281257 * A281259 A281260 A281261


KEYWORD

nonn,base,easy


AUTHOR

Peter M. Chema, Jan 18 2017


STATUS

approved



