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A246561 Least number k such that k concatenated with n is a cube, or 0 if no such k exists. 0
133, 51, 34, 6, 12, 21, 2, 172, 72, 0, 3579, 5, 49, 0, 0, 2, 3890, 0, 593, 0, 689, 0, 1038, 138, 1, 0, 0, 17, 0, 0, 13, 58, 4565, 0, 0, 973, 359, 0, 4930, 0, 5314, 0, 0, 27, 0, 0, 2500, 106, 1176, 0, 1326, 219, 506, 0, 0, 466, 8043, 0, 68, 0, 92, 0, 3007, 1574, 0, 0, 121, 327, 7049, 0, 7535, 548, 9126, 0, 33 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(n) = 0 if and only if n is in A246449.

LINKS

Table of n, a(n) for n=1..75.

EXAMPLE

512 is the smallest cube ending with digit 2, so a(2) = 51.

PROG

(PARI)

b(n)=v=[]; for(k=10^(n-1), 10^n, v=concat(v, k^3%10^n)); v=vecsort(v, , 8); v

w=[]; for(k=1, 250, d=digits(k); if(vecsearch(b(#d), k), w=concat(w, k))); w=vecsort(w, , 8); w;

a(n)=if(!vecsearch(w, n), return(0)); if(vecsearch(w, n), j=1; s=Str(n); while(!ispower(eval(concat(Str(j), s)), 3), j++); return(j))

vector(200, n, a(n))

CROSSREFS

Cf. A000578, A246449, A245631.

Sequence in context: A114534 A147692 A028674 * A003915 A046439 A031188

Adjacent sequences:  A246558 A246559 A246560 * A246562 A246563 A246564

KEYWORD

nonn,base

AUTHOR

Derek Orr, Aug 29 2014

STATUS

approved

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Last modified April 13 17:30 EDT 2021. Contains 342936 sequences. (Running on oeis4.)