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A089294 Smallest prime p_k such that n can be written as a "plus-minus" sum n=sum_(i=1..k)e_i*(p_i)^2 with distinct primes p_i<=p_k, where e_i is 1 or -1. 3
19, 13, 19, 13, 2, 3, 13, 19, 13, 3, 13, 7, 5, 3, 13, 7, 5, 13, 13, 7, 5, 5, 13, 13, 7, 5, 13, 13, 7, 5, 5, 13, 13, 7, 5, 13, 7, 7, 5, 13, 7, 17, 11, 11, 7, 7, 17, 11, 13, 7, 17, 11, 11, 7, 7, 17, 11, 13, 7, 11, 11, 7, 7, 11, 13, 7, 17, 11, 11, 7, 7, 17, 11, 13, 7, 17, 11, 11, 7, 7, 17, 11 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

The first terms where this sequence differs from A088934 are n=22,31,52,87,89,98,118,127,...

LINKS

Table of n, a(n) for n=0..81.

EXAMPLE

a(22)=13 because 22 can be represented as -13^2+11^2+7^2+5^2-2^2.

The corresponding representation with the minimum number of terms is

22=19^2-13^2-11^2-7^2 (A088934(22)=19, A088910(22)=4 terms)

CROSSREFS

The positions of the records in this sequence are given in A089295. Cf. A088910, A088934.

Sequence in context: A323832 A306384 A196188 * A088934 A177923 A155848

Adjacent sequences:  A089291 A089292 A089293 * A089295 A089296 A089297

KEYWORD

nonn

AUTHOR

W. Edwin Clark Nov 06 2003

STATUS

approved

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Last modified December 5 22:37 EST 2019. Contains 329782 sequences. (Running on oeis4.)