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A069062 Numbers k such that k^2-1 and k^2+1 have the same number of positive divisors. 1
2, 3, 12, 30, 42, 60, 68, 102, 108, 112, 123, 128, 162, 168, 198, 200, 212, 213, 252, 294, 302, 312, 318, 333, 336, 338, 372, 387, 447, 448, 450, 462, 498, 502, 522, 542, 578, 592, 598, 600, 606, 612, 648, 672, 678, 708, 717, 752, 762, 795, 808, 810, 812 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..53.

PROG

(PARI) isok(n) = numdiv(n^2-1) == numdiv(n^2+1); \\ Michel Marcus, Nov 24 2013

CROSSREFS

Cf. A193432.

Sequence in context: A260631 A195913 A048085 * A073618 A025560 A247651

Adjacent sequences:  A069059 A069060 A069061 * A069063 A069064 A069065

KEYWORD

easy,nonn

AUTHOR

Benoit Cloitre, Apr 04 2002

STATUS

approved

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Last modified May 30 09:47 EDT 2020. Contains 334724 sequences. (Running on oeis4.)