A095238 - OEIS

A095238

a(1) = 1, a(n) = n*(sum of all previous terms mod n).

1, 2, 0, 12, 0, 18, 35, 32, 9, 90, 11, 72, 117, 98, 30, 240, 34, 162, 247, 200, 63, 462, 69, 288, 425, 338, 108, 756, 116, 450, 651, 512, 165, 1122, 175, 648, 925, 722, 234, 1560, 246, 882, 1247, 968, 315, 2070, 329, 1152, 1617, 1250, 408, 2652, 424, 1458, 2035

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OFFSET

1,2

COMMENTS

An open question is whether the sequence contains zeros except for the 3rd and the 5th number. I checked this up to a(10000), which happens to be 99990000. - Johan Claes, Jun 16 2004

LINKS

Table of n, a(n) for n=1..55.

FORMULA

Appears to satisfy a linear recurrence with characteristic polynomial (1+x)(1+x^3)^2(1-x^3)^3 (checked up to n = 10^4). - Ralf Stephan, Dec 04 2004

EXAMPLE

a(6) = 6*((1 + 2 + 0 + 12 + 0) mod 6) = 18.

MAPLE

A095238:=proc(n) option remember; n*(add(A095238(i), i=1..n-1) mod n) end: A095238(1):=1: seq(A095238(n), n=1..100);

MATHEMATICA

a[1] = 1; a[n_] := a[n] = n*Mod[Sum[a[i], {i, n - 1}], n]; Table[ a[n], {n, 55}] (* Robert G. Wilson v, Jun 16 2004 *)

PROG

(PARI) a=vector(1000); a[1]=1; for(i=2, 1000, a[i]=i*lift(Mod(sum(j=1, i-1, a[j]), i)))

CROSSREFS

Cf. A074143.

Sequence in context: A355783 A053814 A293260 * A167345 A292496 A285480

Adjacent sequences: A095235 A095236 A095237 * A095239 A095240 A095241

KEYWORD

nonn

AUTHOR

Amarnath Murthy, Jun 15 2004

EXTENSIONS

More terms from Alec Mihailovs (alec(AT)mihailovs.com), Robert G. Wilson v and Johan Claes, Jun 16 2004

STATUS

approved