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%I #7 Aug 02 2013 11:12:54
%S 0,2,6,12,20,30,42,56,72,0,0,2,6,12,20,30,42,56,72,2,2,4,8,14,22,32,
%T 44,58,74,6,6,8,12,18,26,36,48,62,78,12,12,14,18,24,32,42,54,68,84,20,
%U 20,22,26,32,40,50,62,76,92,30,30,32,36,42,50,60,72,86,102,42,42,44,48,54
%N Sum of digits squared minus sum of digits of n.
%C Inspired by A071440. The quasi-periodic function. First several terms are pronic numbers A002378. See also A077253.
%H Vincenzo Librandi, <a href="/A077252/b077252.txt">Table of n, a(n) for n = 1..1000</a>
%e a(13)=6 because (1^2+3^2)-(1+3)=6.
%t sd[n_]:= Module[{idn = IntegerDigits[n]}, Total[idn^2 - idn]]; Array[sd, 80] (* _Vincenzo Librandi_, Aug 02 2013 *)
%Y Cf. A071440, A002378, A077253.
%K nonn,base
%O 1,2
%A _Zak Seidov_, Oct 31 2002
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