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A045879 Numbers whose square contains the same digits as some other square. 2

%I #14 Aug 21 2021 13:10:13

%S 12,13,14,16,21,25,31,32,33,36,37,42,44,49,54,64,69,96,98,99,101,102,

%T 103,106,108,110,112,113,120,122,128,129,130,133,135,137,140,144,146,

%U 148,152,153,154,155,157,158,159,160,166,172,174,178,179,181,186,190

%N Numbers whose square contains the same digits as some other square.

%H David A. Corneth, <a href="/A045879/b045879.txt">Table of n, a(n) for n = 1..10000</a>

%e 12^2 = 144 has same digits as 21^2 = 441, so 12 and 21 are in the sequence.

%o (PARI) uptoqdigits(n) = { res = List(); for(i = 3, n, withqdigits(i); ); Set(res); }

%o withqdigits(n) = { my(l = List(), streak); for(i = sqrtint(10^(n-1)), sqrtint(10^n-1), listput(l, [vecsort(digits(i^2)),i])); listsort(l); print(#l); for(i = 1, #l-1, if(l[i][1] == l[i+1][1], listput(res, l[i][2]); streak = 1; , if(streak == 1, listput(res, l[i][2])); streak = 0)); if(streak == 1, listput(res, l[#l][2])); } \\ _David A. Corneth_, Aug 13 2021

%Y Cf. A000290.

%K nonn,base

%O 1,1

%A _Erich Friedman_

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Last modified March 28 12:26 EDT 2024. Contains 371254 sequences. (Running on oeis4.)