A030484 -id:A030484 - cp's OEIS frontend

A030486 When squared gives number composed of digits {2,5,6}.

5, 15, 16, 25, 75, 235, 475, 515, 516, 725, 5125, 7525, 22925, 23585, 72475, 505525, 515415, 2501125, 15008516, 23711235, 72267325, 149081275, 250133275, 256032335, 505228925, 2294919525, 5153315075, 15040686675, 50222133125

Offset: 1

Patrick De Geest

Zhao Hui Du, Table of n, a(n) for n = 1..44
Patrick De Geest, Squares containing at most three distinct digits, Index entries for related sequences
Author?, Source(txt)

Cf. A030484.

Extended and corrected by author 03/2000.

More terms from C. Ronaldo (aga_new_ac(AT)hotmail.com), Jan 03 2005

A119164 Triangular numbers composed of digits {2,5,6}.

Original entry on oeis.org

6, 55, 66, 666, 2556, 5565, 6555, 26565, 255255, 2265256, 5656566, 55656525, 525252666, 2665266555, 2666226566655, 6655522556665, 56625555222225, 265556626652565, 555665666566566, 2626662552255225, 6225222656552266, 26256252552656556, 652265255255252222566

Offset: 1

Giovanni Resta, May 10 2006

Giovanni Resta, Tridigital Triangular Numbers

Cf. A000217, A030484, A119165. See A119033 for a table of cross-references.

Flatten[Table[Select[FromDigits/@Tuples[{2,5,6},n],OddQ[Sqrt[8#+1]]&],{n,16}]] (* Harvey P. Dale, Nov 03 2015 *)

a(n) = A000217(A119165(n)).

a(22)-a(23) from Tyler Busby, Mar 24 2023

cp's OEIS Frontend

A030486 When squared gives number composed of digits {2,5,6}.

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