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A029987 Squares which are palindromes in base 4. 14
0, 1, 25, 289, 441, 4225, 5041, 6889, 66049, 74529, 78961, 100489, 1050625, 1113025, 16785409, 17313921, 17581249, 19368801, 26594649, 26822041, 27258841, 268468225, 272613121, 284428225, 297183121, 4295098369 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,3
LINKS
Patrick De Geest, Palindromic Squares
EXAMPLE
5^2 = 25 in base 4 is 121, which is a palindrome, hence 25 is in the sequence.
6^2 = 36 in base 4 is 210, which is not a palindrome, so 36 is not in the sequence.
MATHEMATICA
palindromicQ[n_, b_:10] := TrueQ[IntegerDigits[n, b] == Reverse[IntegerDigits[n, b]]]; Select[Range[1000]^2, palindromicQ[#, 4] &] (* Alonso del Arte, Mar 04 2017 *)
Select[Range[0, 70000]^2, IntegerDigits[#, 4]==Reverse[IntegerDigits[#, 4]]&] (* Harvey P. Dale, May 07 2022 *)
PROG
(PARI) lista(nn) = for (n=0, nn, d = digits(n^2, 4); if (Vecrev(d) == d, print1(n^2, ", "))); \\ Michel Marcus, Mar 05 2017
CROSSREFS
Cf. A029986.
Sequence in context: A265967 A225873 A351925 * A017582 A335598 A210430
KEYWORD
nonn,base
AUTHOR
STATUS
approved

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Last modified June 24 19:44 EDT 2024. Contains 373690 sequences. (Running on oeis4.)