

A115429


Numbers k such that the concatenation of k with k+8 gives a square.


25



6001, 6433, 11085116, 44496481, 96040393, 115916930617, 227007035017, 274101929528, 434985419768, 749978863753, 996004003993, 1365379857457948, 1410590590957816, 1762388551055953, 2307340946901148, 2700383162251217
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OFFSET

1,1


COMMENTS

Also numbers k such that k concatenated with k+7 gives the product of two numbers which differ by 2.
Also numbers k such that k concatenated with k+4 gives the product of two numbers which differ by 4.
Also numbers k such that k concatenated with k1 gives the product of two numbers which differ by 6.
Also numbers k such that k concatenated with k8 gives the product of two numbers which differ by 8.


LINKS

Table of n, a(n) for n=1..16.


EXAMPLE

6001//6009 = 7747^2, where // denotes concatenation.
96040393//96040400 = 98000200 * 98000202.
96040393//96040397 = 98000199 * 98000203.
96040393//96040392 = 98000198 * 98000204.


CROSSREFS

Cf. A030465, A102567, A115426, A115437, A115428, A115430, A115431, A115432, A115433, A115434, A115435, A115436, A115440.
Cf. A116107, A116109, A116113, A116239.
Cf. A116205, A115430, A116335, A116185, A116187, A116317.
Cf. A116131, A116112, A116152, A116159, A116282.
Sequence in context: A068132 A250514 A343432 * A046395 A143043 A031605
Adjacent sequences: A115426 A115427 A115428 * A115430 A115431 A115432


KEYWORD

base,nonn


AUTHOR

Giovanni Resta, Jan 24 2006


EXTENSIONS

Edited by N. J. A. Sloane, Apr 15 2007


STATUS

approved



