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 A268228 a(n) = sum of digits of (2n + 1)^2. 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 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. FORMULA a(n) = A007953(A016754(n)). - Michel Marcus, Oct 13 2017 MAPLE f:= n -> convert(convert((2*n+1)^2, base, 10), `+`): map(f, [\$0..100]); # Robert Israel, Apr 26 2020 MATHEMATICA Table[Sum[DigitCount[(2 n + 1)^2] [[i]] i, {i, 9}], {n, 0, 70}] (* Vincenzo Librandi, Jul 23 2016, after G. C. Greubel *) PROG (PARI) a(n) = sumdigits((2*n+1)^2); \\ Michel Marcus, Jul 23 2016 (MAGMA) [&+Intseq((2*n+1)^2): n in [0..87] ]; // Vincenzo Librandi, Jul 23 2016 CROSSREFS Bisection of A004159. Cf. A007953, A016754, A268227. Sequence in context: A121911 A010547 A011405 * A131724 A190995 A186830 Adjacent sequences:  A268225 A268226 A268227 * A268229 A268230 A268231 KEYWORD nonn,base AUTHOR N. J. A. Sloane, Jan 31 2016 STATUS approved

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Last modified April 16 05:20 EDT 2021. Contains 343030 sequences. (Running on oeis4.)