A088848 - OEIS

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A088848

Number of prime factors, without 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, 4, 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, 6, 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, 5, 6, 5, 7, 4, 5, 6, 4, 6, 4, 6, 4, 5, 5, 9, 5, 5, 6, 6, 5, 3, 4, 5, 5

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Table of n, a(n) for n=1..100.

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

FORMULA

Omega(n) for n = a^4+b^4 = c^4+d^4 for distinct a, b, c, d. n=635318657, 3262811042, .., 960213785093149760746642, 962608047985759418078417

EXAMPLE

3262811042 = 2*113*2953*4889. Thus 4 is the first entry.

PROG

(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. omegax4py42(n) = { for (i = 1, n, x = eval( Str("%", i) ); y=omega(x); print(y", ") ) }

CROSSREFS

Cf. A003824.

Sequence in context: A046587 A147563 A136213 * A088849 A251539 A123932

Adjacent sequences: A088845 A088846 A088847 * A088849 A088850 A088851

KEYWORD

fini,nonn

AUTHOR

Cino Hilliard, Nov 24 2003

STATUS

approved