A088849 Number of prime factors, with multiplicity, of numbers that can be expressed as the sum of two distinct 4th powers in exactly two distinct ways.
4, 4, 4, 4, 3, 4, 4, 4, 6, 4, 5, 6, 4, 4, 7, 5, 7, 4, 3, 5, 6, 5, 6, 5, 6, 4, 5, 5, 6, 5, 4, 5, 4, 4, 6, 6, 6, 6, 6, 6, 5, 5, 6, 5, 6, 6, 7, 5, 7, 5, 6, 4, 5, 6, 6, 6, 5, 6, 5, 6, 4, 6, 4, 7, 6, 7, 5, 4, 5, 4, 5, 4, 6, 6, 5, 6, 6, 6, 5, 7, 4, 5, 6, 4, 6, 5, 6, 4, 5, 8, 9, 5, 5, 6, 6, 5, 3, 5, 8, 5, 7, 5, 7, 6, 4
Offset: 1
Examples
The 16th entry in the Bernstein Evaluation = 680914892583617 = 17*17*89*61657*429361 = 5 factors. 5 is the 16th entry in the sequence.
Links
- D. J. Bernstein, List of 516 primitive solutions p^4 + q^4 = r^4 + s^4
- Cino Hilliard, p,q,r,s and evaluation of the Bernstein data
- Cino Hilliard, Evaluation of the Bernstein data only
Crossrefs
Cf. A003824.
Programs
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PARI
\ begin a new session and (back slash)r x4data.txt (evaluated Bernstein data) \ to the gp session. This will allow using %1 as the initial value. bigomegax4py42(n) = { for (i = 1, n, x = eval( Str("%", i) ); y=bigomega(x); print(y",") ) }
Formula
Bigomega(n) for n = a^4+b^4 = c^4+d^4 for distinct a, b, c, d. n=635318657, 3262811042, .., 680914892583617, .., 962608047985759418078417