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A059729 Carryless squares n X n base 10.

%I A059729 #34 Mar 08 2023 09:35:43
%S A059729 0,1,4,9,6,5,6,9,4,1,100,121,144,169,186,105,126,149,164,181,400,441,
%T A059729 484,429,466,405,446,489,424,461,900,961,924,989,946,905,966,929,984,
%U A059729 941,600,681,664,649,626,605,686,669,644,621,500,501,504,509,506,505
%N A059729 Carryless squares n X n base 10.
%H A059729 Seiichi Manyama, <a href="/A059729/b059729.txt">Table of n, a(n) for n = 0..9999</a>
%H A059729 David Applegate, Marc LeBrun and N. J. A. Sloane, <a href="http://neilsloane.com/doc/carry1.pdf">Carryless Arithmetic (I): The Mod 10 Version</a>.
%H A059729 <a href="/index/Ca#CARRYLESS">Index entries for sequences related to carryless arithmetic</a>
%e A059729 a(87) is carryless sum of (6)400, (5)60, (5)60 and (4)9, i.e., 400+20+9 = 429.
%o A059729 (Python)
%o A059729 def A059729(n):
%o A059729     s = [int(d) for d in str(n)]
%o A059729     l = len(s)
%o A059729     t = [0]*(2*l-1)
%o A059729     for i in range(l):
%o A059729         for j in range(l):
%o A059729             t[i+j] = (t[i+j] + s[i]*s[j]) % 10
%o A059729     return int("".join(str(d) for d in t)) # _Chai Wah Wu_, Jun 29 2020
%o A059729 (PARI) a(n) = fromdigits(Vec(Pol(digits(n))^2)%10) \\ _Ruud H.G. van Tol_, Dec 07 2022
%Y A059729 Cf. A004520, A059692, A169889, A169963.
%Y A059729 See A087019 (lunar squares) for another version.
%K A059729 base,easy,nonn,look
%O A059729 0,3
%A A059729 _Henry Bottomley_, Feb 20 2001