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A332456
Numbers k such that sigma(sigma(k)) is congruent to 6 modulo 8.
3
9, 67, 163, 193, 201, 202, 271, 338, 469, 489, 505, 547, 579, 606, 670, 673, 729, 813, 982, 1087, 1111, 1123, 1139, 1141, 1153, 1201, 1223, 1351, 1354, 1407, 1414, 1423, 1474, 1515, 1543, 1601, 1630, 1641, 1642, 1791, 1873, 1897, 1930, 1966, 2010, 2017, 2019, 2077, 2083, 2088, 2323, 2326, 2371, 2447, 2455, 2467, 2503
OFFSET
1,1
PROG
(PARI) isA332456(n) = (6==(sigma(sigma(n))%8));
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Feb 15 2020
STATUS
approved