OFFSET
1,1
COMMENTS
All positive multiples of 5 are terms of the sequence.
REFERENCES
Amarnath Murthy, Smarandache friendly numbers and a few more sequences, Smarandache Notions Journal, Vol. 12, No. 1-2-3, Spring 2001.
LINKS
Luca Onnis, On the general Smarandache's sigma product of digits, arXiv:2203.07227 [math.GM], 2022.
FORMULA
EXAMPLE
MATHEMATICA
Flatten[Position[(Accumulate[Times @@@ IntegerDigits[Range[2, 10000, 2]]]/
Accumulate[Times @@@ IntegerDigits[Range[1, 9999, 2]]]), 4/5]]
PROG
(PARI) pd(n) = my(d = digits(n)); prod(i=1, #d, d[i]);
isok(k) = sum(i=1, k, pd(2*i))/sum(i=1, k, pd(2*i-1)) == 4/5; \\ Michel Marcus, Mar 21 2022
CROSSREFS
KEYWORD
nonn
AUTHOR
Luca Onnis, Mar 20 2022
STATUS
approved