A039283 - OEIS

A039283

Numbers whose base-5 representation has the same nonzero number of 0's and 1's.

5, 27, 28, 29, 35, 40, 45, 51, 55, 76, 80, 101, 105, 126, 130, 137, 138, 139, 142, 143, 144, 147, 148, 149, 150, 177, 178, 179, 185, 190, 195, 202, 203, 204, 210, 215, 220, 227, 228, 229, 235, 240, 245, 257, 258, 259, 261, 266, 271, 277, 278, 279, 285, 290

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..54.

MATHEMATICA

Select[Range[300], DigitCount[#, 5, 0]==DigitCount[#, 5, 1]>0&] (* Harvey P. Dale, Oct 16 2019 *)

PROG

(Python)

from sympy.ntheory import count_digits

def ok(n): c = count_digits(n, 5); return 0 in c and 1 in c and c[0] == c[1]

print(list(filter(ok, range(291)))) # Michael S. Branicky, May 27 2021

(PARI) is(n) = my(d=vecsort(digits(n, 5)), e=vector(#d), f=vector(#d, t, 1), side=#setintersect(d, e), sidf=#setintersect(d, f)); side==sidf && side > 0 \\ Felix Fröhlich, May 27 2021

CROSSREFS

Cf. A031443, A039275, A039277, A039293, A039308, A039329, A039357, A039393, A039438, A039493.

Sequence in context: A097088 A196009 A091721 * A045162 A056735 A298441

Adjacent sequences: A039280 A039281 A039282 * A039284 A039285 A039286

KEYWORD

nonn,base,easy

AUTHOR

Olivier Gérard

STATUS

approved