A268228 a(n) = sum of digits of (2n + 1)^2.
1, 9, 7, 13, 9, 4, 16, 9, 19, 10, 9, 16, 13, 18, 13, 16, 18, 10, 19, 9, 16, 22, 9, 13, 7, 9, 19, 10, 18, 16, 13, 27, 13, 25, 18, 10, 19, 18, 25, 13, 18, 31, 16, 27, 19, 19, 27, 16, 22, 18, 4, 16, 9, 19, 19, 9, 25, 13, 27, 13, 16, 18, 19, 19, 18, 16, 31, 18, 31, 16, 27, 19, 10, 18, 7, 13, 18
Offset: 0
Links
- Robert Israel, Table of n, a(n) for n = 0..10000
- 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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Magma
[&+Intseq((2*n+1)^2): n in [0..87] ]; // Vincenzo Librandi, Jul 23 2016
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Maple
f:= n -> convert(convert((2*n+1)^2,base,10),`+`): map(f, [$0..100]); # Robert Israel, Apr 26 2020
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Mathematica
Table[Sum[DigitCount[(2 n + 1)^2] [[i]] i, {i, 9}], {n, 0, 70}] (* Vincenzo Librandi, Jul 23 2016, after G. C. Greubel *) -
PARI
a(n) = sumdigits((2*n+1)^2); \\ Michel Marcus, Jul 23 2016