

A080197


13smooth numbers: i.e. numbers whose prime divisors are all <= 13.


13



1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 18, 20, 21, 22, 24, 25, 26, 27, 28, 30, 32, 33, 35, 36, 39, 40, 42, 44, 45, 48, 49, 50, 52, 54, 55, 56, 60, 63, 64, 65, 66, 70, 72, 75, 77, 78, 80, 81, 84, 88, 90, 91, 96, 98, 99, 100, 104, 105, 108, 110, 112, 117, 120
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OFFSET

1,2


COMMENTS

Numbers of the form 2^r*3^s*5^t*7^u*11^v*13^w with r, s, t, u, v, w >= 0.


LINKS

Table of n, a(n) for n=1..69.


EXAMPLE

33 = 3*11 and 39 = 3*13 are terms but 34 = 2*17 is not.


MATHEMATICA

mx = 120; Sort@ Flatten@ Table[ 2^i*3^j*5^k*7^l*11^m*13^n, {i, 0, Log[2, mx]}, {j, 0, Log[3, mx/2^i]}, {k, 0, Log[5, mx/(2^i*3^j)]}, {l, 0, Log[7, mx/(2^i*3^j*5^k)]}, {m, 0, Log[11, mx/(2^i*3^j*5^k*7^l)]}, {n, 0, Log[13, mx/(2^i*3^j*5^k*7^l*11^m)]}] (* Robert G. Wilson v, Aug 17 2012 *)


PROG

(PARI) test(n)= {m=n; forprime(p=2, 13, while(m%p==0, m=m/p)); return(m==1)} for(n=1, 200, if(test(n), print1(n", ")))
(MAGMA) [n: n in [1..150]  PrimeDivisors(n) subset PrimesUpTo(13)]; // Bruno Berselli, Sep 24 2012


CROSSREFS

Cf. A000079, A080196. For psmooth numbers with other values of p, see A003586, A051037, A002473, A051038, A080681, A080682, A080683.
Sequence in context: A102800 A072676 A235986 * A115847 A204315 A032966
Adjacent sequences: A080194 A080195 A080196 * A080198 A080199 A080200


KEYWORD

easy,nonn


AUTHOR

Klaus Brockhaus, Feb 10 2003


STATUS

approved



