A069600 -id:A069600 - cp's OEIS frontend

A069601 Smallest triangular number containing all the digits of numbers from 1 to n.

1, 21, 231, 12403, 24531, 235641, 2467531, 13862745, 153694278, 10429651378, 1017139458621, 101114872391625, 10111496127133528, 1011137441915312286, 101111293764315411825, 10111111491815764232356, 1011111155214617733491628, 101111111617874325294116835

Offset: 1

Amarnath Murthy, Mar 25 2002

For a(10) and higher, all duplicated digits must be in the term (for example a(10) has two 1's).

Conjecture: except for a(4), the digits of a(n) are exactly all the digits of numbers from 1 to n. - Chai Wah Wu, May 18 2020

			a(5) = 219453 = T(662) contains digits 1, 2, 3, 4 and 5.

Chai Wah Wu, Table of n, a(n) for n = 1..29

Cf. A088628, A069600.

Corrected and extended by Larry Reeves (larryr(AT)acm.org), Jan 24 2003

a(15)-a(18) from Chai Wah Wu, May 18 2020

A263404 Smallest square containing the first n primes as substrings.

Original entry on oeis.org

25, 324, 3025, 35721, 11730625, 71132356, 1132591716, 17136119025, 1923311317225, 58191311792329, 58191311792329, 231372178511929, 1722376411319529, 1134152319174379129, 472643754131992311729, 17298113195343723473641, 419723711317595314724329, 4319231361106417537475929

Offset: 1

Emmanuel Vantieghem, Oct 17 2015

The sequence is infinite.

			a(6) = 71132356 = 8464^2 contains 2, 3, 5, 7, 11 and 13 as substrings and no smaller square has that property.

Cf. A054261, A069600.

Do[k = 1; While[! AllTrue[Prime@ Range@ n, StringContainsQ[ToString[k^2], ToString@ #] &], k++]; Print[k^2], {n, 9}] (* Michael De Vlieger, Oct 19 2015, Version 10 *)

a(15)-a(16) from Bert Dobbelaere, Oct 28 2018

a(17)-a(18) from Giovanni Resta, Aug 27 2019

cp's OEIS Frontend

A069601 Smallest triangular number containing all the digits of numbers from 1 to n.

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