login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A217408
3-adic valuation of A217407.
2
35, 20, 59, 42, 63, 5, 69, 73, 21, 43, 71, 1149
OFFSET
1,1
COMMENTS
See main sequence for rationale.
EXAMPLE
The first number that has only 3 and 5 as prime factors and has prime counts of each digit 0-9 in its decimal representation is (3^35)*(5^17), so, corresponding to that being A217407(1), this sequence's first term is 35.
PROG
(PARI) prDigits(n)=my(d=digits(n), v=vector(10)); for(i=1, #d, v[d[i]+1]++); for(i=1, 10, if(!isprime(v[i]), return(0))); 1
list(lim)=my(v=List(), t); for(a=0, log(lim+.5)\log(5), t=5^a; while(t<=lim, if(prDigits(t), listput(v, t)); t*=3)); apply(k -> valuation(k, 3), vecsort(Vec(v))) \\ Charles R Greathouse IV, Sep 19 2013
CROSSREFS
Sequence in context: A088830 A033355 A267402 * A266057 A267341 A174027
KEYWORD
nonn,base,less
AUTHOR
James G. Merickel, Oct 02 2012
STATUS
approved