The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A239210 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A239210

Numbers k such that k^2 is not divisible by any of its nonzero digits.
(history; published version)

#6 by Colin Barker at Thu Oct 30 06:59:34 EDT 2014

LINKS

Colin Barker, <a href="/A239210/b239210.txt">Table of n, a(n) for n = 1..1000</a>

STATUS

approved

editing

#5 by Bruno Berselli at Fri Mar 14 07:36:39 EDT 2014

STATUS

proposed

approved

#4 by Colin Barker at Wed Mar 12 10:30:31 EDT 2014

STATUS

editing

proposed

#3 by Colin Barker at Wed Mar 12 10:22:52 EDT 2014

NAME

allocated for Colin BarkerNumbers n such that n^2 is not divisible by any of its nonzero digits.

DATA

7, 17, 23, 26, 47, 53, 67, 73, 76, 77, 83, 86, 94, 97, 143, 157, 163, 167, 173, 176, 187, 193, 194, 197, 223, 233, 236, 244, 253, 256, 257, 260, 274, 277, 283, 287, 293, 307, 313, 314, 457, 473, 493, 503, 517, 523, 527, 533, 547, 553, 577, 583, 587, 607, 613

OFFSET

1,1

EXAMPLE

53 is in the sequence because 53^2 = 2809 which is not divisible by 2, 8 or 9.

PROG

(PARI) isOK(n) = my(v=vecsort(digits(n^2), , 8)); for(i=1+(v[1]==0), #v, if(n^2%v[i]==0, return(0))); 1

s=[]; for(n=1, 1000, if(isOK(n), s=concat(s, n))); s

CROSSREFS

Cf. A239211, A239212, A239213.

KEYWORD

allocated

nonn,base

AUTHOR

Colin Barker, Mar 12 2014

STATUS

approved

editing

#2 by Colin Barker at Wed Mar 12 10:14:38 EDT 2014

KEYWORD

allocating

allocated

#1 by Colin Barker at Wed Mar 12 10:14:38 EDT 2014

NAME

allocated for Colin Barker

KEYWORD

allocating

STATUS

approved