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A166376 Triangle in which n-th row (n>1) gives prime factors of n^2 + 1 with repetition. 0
2, 5, 2, 5, 17, 2, 13, 37, 2, 5, 5, 5, 13, 2, 41, 101, 2, 61, 5, 29, 2, 5, 17, 197, 2, 113, 257, 2, 5, 29, 5, 5, 13, 2, 181, 401, 2, 13, 17, 5, 97, 2, 5, 53, 577, 2, 313, 677, 2, 5, 73, 5, 157, 2, 421, 17, 53, 2, 13, 37, 5, 5, 41 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..63.

EXAMPLE

Since 13^2+1 = 170 = 2*5*17, the three terms 2, 5, 17 appear in the sequence.

PROG

(PARI) row(n)={m=n^2+1; while(m!=1, p=factor(m)[1, 1]; print(p); m=m/p)}

CROSSREFS

Cf. A027746 A002522

Sequence in context: A107060 A016589 A151572 * A089122 A321577 A268789

Adjacent sequences:  A166373 A166374 A166375 * A166377 A166378 A166379

KEYWORD

nonn,tabf

AUTHOR

Michael B. Porter, Oct 13 2009

STATUS

approved

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Last modified February 21 01:15 EST 2019. Contains 320364 sequences. (Running on oeis4.)