OFFSET
1,1
COMMENTS
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
FORMULA
2^k occurs in the sequence g(Q_k) - g(Q_k-1)+1 times, where g is the binary order and Q_k is the k-th primorial number.
EXAMPLE
128 occurs in the sequence from index 19 and 23 inclusively (5 times) because the 7th primorial number Q_7=510510 has binary order 19 and Q_8, the next one is 9699690 has binary order 24 (it is between 2^23 and 2^24).
PROG
(PARI) v=List([2]); n=0; P=p=2; forprime(q=3, 97, n++; for(i=1, log(P*q)\log(2)-log(P)\log(2), listput(v, 1<<n)); P*=p=q); Vec(v) \\ Charles R Greathouse IV, Apr 08 2012
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved