A268227 a(n) = sum of digits of (2n)^2.
0, 4, 7, 9, 10, 1, 9, 16, 13, 9, 4, 16, 18, 19, 19, 9, 7, 13, 18, 13, 7, 18, 19, 10, 9, 7, 13, 18, 13, 16, 9, 19, 19, 18, 16, 13, 18, 22, 25, 18, 10, 19, 18, 25, 22, 9, 22, 25, 18, 19, 1, 9, 16, 13, 18, 4, 16, 27, 19, 19, 9, 25, 22, 27, 22, 16, 18, 28, 28, 18, 16, 13, 18, 13, 16, 9, 10, 19, 18
Offset: 0
Links
- Harvey P. Dale, Table of n, a(n) for n = 0..1000
- H. I. Okagbue, M. O. Adamu, S. A. Iyase, A. A. Opanuga, Sequence of Integers Generated by Summing the Digits of their Squares, Indian Journal of Science and Technology, Vol 8(15), DOI: 10.17485/ijst/2015/v8i15/69912, July 2015.
Programs
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Mathematica
Total[IntegerDigits[#]]&/@((2*Range[0,80])^2) (* Harvey P. Dale, Sep 14 2016 *)
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PARI
a(n) = sumdigits((2*n)^2); \\ Michel Marcus, Jul 23 2016