OFFSET
2,2
COMMENTS
For n = 3 to 54 there are no terms 1 less than a power of 2, so the base 2 product does not contribute to the sum for any of these terms. In the same range the base 3 product only contributes for n = 8, while the base 4 product contributes for n = 6, 8, 9, 10, 18, 23, 24, 31, 42.
EXAMPLE
a(6) = 9 as 9 = 1001_2 = 100_3 = 21_4 = 14_5 = 13_6, and the sum of the products of the digits in each base is 0 + 0 + 2 + 4 + 3 = 9.
a(10) = 86 as 86 = 1010110_2 = 10012_3 = 1112_4 = 321_5 = 222_6 = 152_7 = 126_8 = 105_9 = 86_10, and the sum of the products of the digits in each base is 0 + 0 + 2 + 6 + 8 + 10 + 12 + 0 + 48 = 86.
CROSSREFS
KEYWORD
sign,base
AUTHOR
Scott R. Shannon, Oct 07 2024
STATUS
approved