A153806 - OEIS

A153806

Strobogrammatic cyclops numbers.

0, 101, 609, 808, 906, 11011, 16091, 18081, 19061, 61019, 66099, 68089, 69069, 81018, 86098, 88088, 89068, 91016, 96096, 98086, 99066, 1110111, 1160911, 1180811, 1190611, 1610191, 1660991, 1680891, 1690691, 1810181, 1860981

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

Intersection of A000787 and A134808.

LINKS

Kenny Lau, Table of n, a(n) for n = 1..20000

EXAMPLE

1680891 is a member because it is the same upside down (A000787) and also a cyclops number (A134808).

MATHEMATICA

Select[Range[10^7], And[OddQ@ Length@#, Part[#, Ceiling[Length[#]/2]] == 0, Times @@ Boole@ Map[MemberQ[{0, 1, 6, 8, 9}, #] &, Union@ #] == 1, Count[#, 0] == 1, (Take[#, Floor[Length[#]/2]] /. {6 -> 9, 9 -> 6}) ==

Reverse@ Take[#, -Floor[Length[#]/2]]] &@ IntegerDigits@ # &] (* Michael De Vlieger, Jul 05 2016 *)

PROG

(Python)

import sys

f = open('b153806.txt', 'w')

i = 1

n = 0

a = [""]

r = [""] #reversed strobogrammatically

while True:

....for x, y in zip(a, r):

........f.write(str(i)+" "+x+"0"+y+"\n")

........i += 1

........if i>20000:

............f.close()

............sys.exit()

....a = sum([[x+"1", x+"6", x+"8", x+"9"] for x in a], [])

....r = sum([["1"+x, "9"+x, "8"+x, "6"+x] for x in r], [])

# Kenny Lau, Jul 05 2016

CROSSREFS

Cf. A000787, A007597, A134808, A134809, A138131, A138148, A153807.

Sequence in context: A060012 A142507 A131697 * A227521 A364147 A171813

Adjacent sequences: A153803 A153804 A153805 * A153807 A153808 A153809

KEYWORD

base,easy,nonn

AUTHOR

Omar E. Pol, Jan 15 2009

EXTENSIONS

Extended beyond 11011 by R. J. Mathar, Jan 17 2009

STATUS

approved