

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
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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



