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A199924 Numbers k such that the sum of the largest and the smallest prime divisor of k^2 + 1 equals the sum of the other distinct prime divisors. 1
948, 1560, 1772, 2153, 2697, 8487, 11293, 12553, 13236, 18065, 32247, 36984, 40452, 43999, 55945, 94536, 100512, 107607, 127224, 134223, 214641, 218783, 366937, 425808, 429855, 595471, 620865, 645327, 757382, 850416, 875784, 1241106, 1330849, 1363977, 1387689 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Generalization of A192770 and A192771.

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..200

EXAMPLE

2697 is in the sequence because 2697^2 + 1 = 7273810 has five distinct divisors  2, 5, 41, 113, 157 and 157 + 2 = 5 + 41 + 113 = 159.

MATHEMATICA

Select[Range[1400000], Plus@@((pl=First/@FactorInteger[#^2+1])/2)==pl[[1]]+pl[[-1]]&](* program of Ray Chandler adapted for this sequence - see A199745 *)

CROSSREFS

Cf. A180278, A192771, A192770.

Sequence in context: A257722 A093247 A248785 * A215950 A192770 A187627

Adjacent sequences:  A199921 A199922 A199923 * A199925 A199926 A199927

KEYWORD

nonn

AUTHOR

Michel Lagneau, Nov 12 2011

STATUS

approved

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Last modified October 22 13:49 EDT 2021. Contains 348170 sequences. (Running on oeis4.)