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A030155 Odd n such that in n^2 the parity of digits alternates. 2
1, 3, 5, 7, 9, 11, 13, 19, 23, 27, 31, 69, 81, 111, 113, 119, 127, 137, 181, 187, 237, 269, 273, 277, 281, 311, 461, 463, 539, 661, 673, 677, 689, 819, 831, 1019, 1027, 1111, 1113, 1119, 1127, 1137, 1269, 1277, 1287, 1361, 1369, 1377, 1863, 1969 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Giovanni Resta, Table of n, a(n) for n = 1..10000

MATHEMATICA

altQ[n_] := n < 10 || Union[Total /@ Partition[ Mod[ IntegerDigits@n, 2], 2, 1]] == {1}; Select[ Range[1, 2000, 2], altQ[#^2] &] (* Giovanni Resta, Aug 16 2018 *)

CROSSREFS

Cf. A030151, A030152, A030156, A030157, A030158.

Sequence in context: A133854 A239008 A291343 * A143448 A226484 A261213

Adjacent sequences:  A030152 A030153 A030154 * A030156 A030157 A030158

KEYWORD

nonn,base

AUTHOR

Patrick De Geest

EXTENSIONS

Offset changed by Giovanni Resta, Aug 16 2018

STATUS

approved

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Last modified November 13 04:20 EST 2019. Contains 329085 sequences. (Running on oeis4.)