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A180436 Palindromic numbers which are sum of consecutive squares. 3

%I

%S 1,4,5,9,55,77,121,181,313,434,484,505,545,595,636,676,818,1001,1111,

%T 1441,1771,4334,6446,10201,12321,14641,17371,17871,19691,21712,40804,

%U 41214,42924,44444,44944,46564,51015,65756,69696,81818,94249,97679,99199

%N Palindromic numbers which are sum of consecutive squares.

%C In more than one way: 554455, 9343439, ... (A267600) - _Robert G. Wilson v_, May 28 2012

%H Giovanni Resta, <a href="/A180436/b180436.txt">Table of n, a(n) for n = 1..10400</a> (terms < 10^18, first 228 terms from Robert G. Wilson v)

%e 1001 is in the sequence because 1001 is palindromic and it can be written as sum of consecutive squares (1001 = 4^2 + 5^2 + 6^2 + ... + 13^2 + 14^2).

%t palQ[n_Integer] := Block[{idn = IntegerDigits[n]}, idn == Reverse[idn]]; lst = {}; k = 1; While[k < 1000, AppendTo[lst, Select[ Accumulate[ Range[k, 1000]^2], palQ]]; lst = Union@ Flatten@ lst; k++]; Select[lst, # < 10^6 &] (* _Robert G. Wilson v_, May 28 2012 *)

%Y Cf. A002113, A002779, A034705, A216446, A267600.

%K nonn,easy,base

%O 1,2

%A _Zhining Yang_, Jan 19 2011

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Last modified August 6 11:55 EDT 2020. Contains 336246 sequences. (Running on oeis4.)