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A202260 Right-truncatable composites: every decimal prefix is a composite number. 7
4, 6, 8, 9, 40, 42, 44, 45, 46, 48, 49, 60, 62, 63, 64, 65, 66, 68, 69, 80, 81, 82, 84, 85, 86, 87, 88, 90, 91, 92, 93, 94, 95, 96, 98, 99, 400, 402, 403, 404, 405, 406, 407, 408, 420, 422, 423, 424, 425, 426, 427, 428, 429, 440, 441, 442, 444, 445, 446, 447, 448 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Subsequence of A202259.

LINKS

Stanislav Sykora, Table of n, a(n) for n = 1..10000

PROG

(PARI) isComposite(n) = (n>2)&&(!isprime(n));

isRightTruncatableComposite(n, b=10) = {my(k=b); if(!isComposite(n), return(0); ); while(n\k>0, if(!isComposite(n\k), return(0); ); k*=b); return(1); } \\ Stanislav Sykora, Feb 15 2015

CROSSREFS

Cf. A012883 (right-truncatable noncomposites), A202259 (right-truncatable nonprimes), A024770 (right-truncatable primes).

Cf. A254750, A254752, A254754, A254755 (left-truncatable composites).

Sequence in context: A099071 A156673 A073866 * A001744 A113624 A113591

Adjacent sequences:  A202257 A202258 A202259 * A202261 A202262 A202263

KEYWORD

nonn,base

AUTHOR

Jaroslav Krizek, Dec 25 2011

STATUS

approved

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Last modified January 15 20:47 EST 2019. Contains 319184 sequences. (Running on oeis4.)