A272264 Numbers that become a different number when flipped upside down.

6, 9, 16, 18, 19, 61, 66, 68, 81, 86, 89, 91, 98, 99, 106, 108, 109, 116, 118, 119, 161, 166, 168, 169, 186, 188, 189, 191, 196, 198, 199, 601, 606, 608, 611, 616, 618, 661, 666, 668, 669, 681, 686, 688, 691, 696, 698, 699, 801, 806, 809, 811, 816, 819, 861, 866, 868, 869, 881, 886, 889

Offset

1,1

Comments

Although 2 and 5 flipped upside down on a digital clock are numbers, they are not permitted here. - David A. Corneth, May 22 2016

Links

A. D. Skovgaard, Table of n, a(n) for n = 1..10000

Prog

(PARI) is(n) = {my(d=digits(n), dr); if(d[#d]==0 || #setminus(Set(d), Set([0, 1, 6, 8, 9])) !=0, return(0), dr=vector(#d)); for(i=1, #d, dr[#d-i+1] = if(d[i]==6||d[i]==9, 15-d[i], d[i])); dr!=d} \\ David A. Corneth, May 22 2016

Crossrefs

Cf. A000787, A045574.

Sequence in context: A242183 A300564 A316050 * A316051 A316052 A316053

Adjacent sequences: A272261 A272262 A272263 * A272265 A272266 A272267

Keyword

base,easy,nonn

Author

A. D. Skovgaard, Apr 24 2016

Status

approved