Search: id:A133033 Results 1-1 of 1 results found. %I A133033 %S A133033 3,5,9,13,25,33,37,61,121,177,213,253,1041,1213,2557,4405,4561,6433, %T A133033 8505,8845,19377,19881,22425,39873,43401,46417,88993,172485,221005, %U A133033 264097,432181,1513677,1718865,2515573,2796537,5952441,6042753,13945185 %N A133033 Number of proper divisors of n-th even perfect number. %C A133033 Perfect numbers: A000396(n) = 2^a(n) - 2^A090748(n), assuming there are no odd perfect numbers. %C A133033 Also, a(n) is equal to the number of bits in A135650(n), the n-th even perfect number written in base 2. %H A133033 C. K. Caldwell, "Top Twenty" page, Mersenne Primes. %H A133033 O. E. Pol, Determinacion geometrica de los numeros primos y perfectos. %F A133033 a(n) = A061645(n) - 1, assuming there are no odd perfect numbers. %F A133033 a(n) = A000043(n) + A090748(n) = 2*A000043(n) - 1 = 2*A090748(n) + 1. %Y A133033 Cf. A135650. %Y A133033 Sequence in context: A052282 A001993 A153263 this_sequence A145365 A146433 A134672 %Y A133033 Adjacent sequences: A133030 A133031 A133032 this_sequence A133034 A133035 A133036 %K A133033 nonn %O A133033 1,1 %A A133033 Omar E. Pol (info(AT)polprimos.com), Oct 27 2007, Feb 23 2008, Apr 28 2009 Search completed in 0.001 seconds