OFFSET
1,1
COMMENTS
See main sequence, A217404.
EXAMPLE
A217404(1)=(2^36)*(7^15), so this sequence's first term is 15, the exponent on 7 in the main sequence.
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(7), t=7^a; while(t<=lim, if(prDigits(t), listput(v, t)); t<<=1)); apply(k -> valuation(k, 7), vecsort(Vec(v))) \\ Charles R Greathouse IV, Sep 19 2013
CROSSREFS
KEYWORD
nonn,base,more
AUTHOR
James G. Merickel, Oct 02 2012
STATUS
approved