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A218795 Numbers that can be written in more than 1 way as p^2 + 3pq + q^2 with primes p < q. 1
671, 1595, 3629, 3839, 4661, 4895, 5771, 8459, 11495, 13079, 17951, 19829, 21251, 22895, 23411, 34751, 40211, 40799, 43829, 45791, 46031, 47795, 49001, 53009, 57209, 57959, 60119, 60491, 64829, 67595, 70661, 78755, 83201, 89249, 98879 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

According to the comment in A218771, there is no prime in this sequence.

The subsequence of terms allowing more than 2 decompositions of the given form starts 136895, 266741, 716441, 902495, 941501, 963281, 1003295, 1033241, 1236539, 1245431, 1439345, 1463495, 1692995, 2300045, 2430461, 3016145, 3238289,...

LINKS

Table of n, a(n) for n=1..35.

EXAMPLE

a(1) = 671 = p^2+3pq+q^2 for (p,q)=(2,23) and (5,19), is the least term to allow more than 1 decomposition of the given form.

CROSSREFS

Cf. A218794 for PARI code and further discussion.

Sequence in context: A235101 A232388 A172963 * A281526 A053085 A057695

Adjacent sequences:  A218792 A218793 A218794 * A218796 A218797 A218798

KEYWORD

nonn

AUTHOR

M. F. Hasler, Nov 05 2012

STATUS

approved

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Last modified March 26 20:35 EDT 2019. Contains 321533 sequences. (Running on oeis4.)