67176domain: NAppears in sequencesNumber of Twopins positions.at n=27A005690Palindromes which are the sum of a twin prime pair.at n=7A037076Palindromes with exactly 7 prime factors (counted with multiplicity).at n=8A046333a(n) = Sum_{j=1..n} j*n^(n+1-j).at n=5A347274