

A115428


Numbers n such that the concatenation of n with n+5 gives a square.


19



1, 4, 20, 31, 14564, 38239, 69919, 120395, 426436, 902596, 7478020, 9090220, 6671332084, 8114264059, 8482227259, 9900250996, 2244338786836, 2490577152964, 2509440638591, 2769448208395, 7012067592220
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OFFSET

1,2


COMMENTS

Also numbers n such that n concatenated with n+1 gives the product of two numbers which differ by 4.
Also numbers n such that n concatenated with n+4 gives the product of two numbers which differ by 2.


LINKS

Table of n, a(n) for n=1..21.


EXAMPLE

14564_14569 = 38163^2.


CROSSREFS

Cf. A030465, A102567, A115426, A115437, A115429, A115430, A115431, A115432, A115433, A115434, A115435, A115436, A115439.
Cf. A116125, A116099, A116167, A116297, A116177, A116171, A116185, A116315.
Sequence in context: A181433 A079454 A205670 * A172624 A043880 A030002
Adjacent sequences: A115425 A115426 A115427 * A115429 A115430 A115431


KEYWORD

nonn,base


AUTHOR

Giovanni Resta, Feb 06 2006


EXTENSIONS

Edited by N. J. A. Sloane, Apr 13 2007


STATUS

approved



