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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. 2
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

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Last modified December 5 10:45 EST 2019. Contains 329751 sequences. (Running on oeis4.)