The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A062691

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A062691

Triangular numbers that contain exactly 2 different digits.
(history; published version)

#25 by Susanna Cuyler at Sun Sep 15 13:49:49 EDT 2019

STATUS

proposed

approved

#24 by Michel Marcus at Sun Sep 15 13:10:05 EDT 2019

STATUS

editing

proposed

#23 by Michel Marcus at Sun Sep 15 13:09:51 EDT 2019

PROG

(PARI) for(k=0, 1e8, 1e5, if(#Set(digits(j=k*(k+1)/2))==2, print1(j", "))) \\ Seiichi Manyama, Sep 15 2019

STATUS

proposed

editing

Discussion

Sun Sep 15

13:10

Michel Marcus: 10^8 would take too much time

#22 by Seiichi Manyama at Sun Sep 15 11:10:19 EDT 2019

STATUS

editing

proposed

#21 by Seiichi Manyama at Sun Sep 15 10:46:59 EDT 2019

COMMENTS

From _For n > 2, A309597(n) is a term. - _Seiichi Manyama_, Sep 15 2019: (Start)

A118668(a(n)) = 2.

For n > 2, A309597(n) is a term. (End)

CROSSREFS

Cf. A000217, A045914 (all digits the same), A118668, A213516, A213518, A309597.

#20 by Seiichi Manyama at Sun Sep 15 10:43:54 EDT 2019

COMMENTS

From _Seiichi Manyama_, Sep 15 2019: (Start)

#19 by Seiichi Manyama at Sun Sep 15 10:43:29 EDT 2019

COMMENTS

From Seiichi Manyama_, Sep 15 2019: (Start)

For n > 2, A309597(n) is a term. - _Seiichi Manyama_, Sep 15 2019(End)

#18 by Seiichi Manyama at Sun Sep 15 10:40:12 EDT 2019

COMMENTS

A118668(a(n)) = 2.

CROSSREFS

Cf. A000217, A045914 (all digits the same), A118668, A213516, A213518, A309597.

#17 by Seiichi Manyama at Sun Sep 15 10:38:55 EDT 2019

CROSSREFS

Cf. A000217, A045914, (all digits the same), A213516, A213518, A309597.

#16 by Seiichi Manyama at Sun Sep 15 10:33:51 EDT 2019

LINKS

Seiichi Manyama, <a href="/A062691/b062691.txt">Table of n, a(n) for n = 1..51</a>