

A351896


Numbers k such that k and k+2 both have an equal number of odd and even digits in their factorialbase representations.


1



71, 743, 791, 839, 862, 910, 983, 1031, 1079, 1102, 1150, 1223, 1271, 1319, 1342, 1390, 1583, 1631, 1823, 1871, 2063, 2111, 2183, 2231, 2279, 2302, 2350, 2423, 2471, 2519, 2542, 2590, 2663, 2711, 2759, 2782, 2830, 3023, 3071, 3263, 3311, 3503, 3551, 3623, 3671, 3719
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OFFSET

1,1


LINKS



EXAMPLE

71 is a term since the factorialbase representations of 71 and 73 are 2321 and 3001, respectively, and both have 2 odd digits and 2 even digits.


MATHEMATICA

max = 7; fctBaseDigits[n_] := IntegerDigits[n, MixedRadix[Range[max, 2, 1]]]; s = Select[Range[1, max!], EvenQ[Length[(d = fctBaseDigits[#])]] && Count[d, _?EvenQ] == Length[d]/2 &]; ind = Position[Differences[s], 2] // Flatten; s[[ind]]


CROSSREFS



KEYWORD

nonn,base


AUTHOR



STATUS

approved



