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n * last digit of n.
2

%I #19 Jul 06 2021 18:27:38

%S 0,1,4,9,16,25,36,49,64,81,0,11,24,39,56,75,96,119,144,171,0,21,44,69,

%T 96,125,156,189,224,261,0,31,64,99,136,175,216,259,304,351,0,41,84,

%U 129,176,225,276,329,384,441,0,51,104,159,216,275,336,399,464,531,0,61,124

%N n * last digit of n.

%H Harry J. Smith, <a href="/A063462/b063462.txt">Table of n, a(n) for n = 0..1000</a>

%H <a href="/index/Rec#order_20">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,0,0,0,0,0,0,2,0,0,0,0,0,0,0,0,0,-1).

%F G.f.: x*(9*x^18 +16*x^17 +21*x^16 +24*x^15 +25*x^14 +24*x^13 +21*x^12 +16*x^11 +9*x^10 +81*x^8 +64*x^7 +49*x^6 +36*x^5 +25*x^4 +16*x^3 +9*x^2 +4*x +1) / ((x -1)^2*(x +1)^2*(x^4 -x^3 +x^2 -x +1)^2*(x^4 +x^3 +x^2 +x +1)^2). - _Colin Barker_, Feb 07 2014

%t Table[n NumberDigit[n,0],{n,0,70}] (* Requires Mathematica version 12 or later *) (* _Harvey P. Dale_, Jul 06 2021 *)

%o (PARI) a(n)=n%10*n; j=[]; for(n=0,200,j=concat(j,a(n))); j

%o (PARI) { for (n=0, 1000, write("b063462.txt", n, " ", n%10*n) ) } \\ _Harry J. Smith_, Aug 22 2009

%K base,easy,nonn

%O 0,3

%A _Jason Earls_, Jul 26 2001