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A331435
a(n) is the least positive k such that A028916(n) - k^2 is a fourth power.
8
1, 2, 1, 6, 5, 4, 10, 11, 10, 14, 15, 1, 14, 5, 9, 20, 21, 24, 19, 4, 6, 26, 26, 12, 14, 29, 16, 31, 29, 22, 24, 31, 34, 1, 26, 5, 28, 35, 40, 19, 41, 39, 44, 38, 29, 45, 42, 4, 6, 35, 51, 16, 46, 20, 51, 54, 55, 56, 56, 30, 52, 54, 34, 36, 56, 58, 40, 9, 11
OFFSET
1,2
EXAMPLE
The first terms, alongside A028916(n), are:
n a(n) A028916(n)
-- ---- ----------------
1 1 2 = 1^2 + 1^4
2 2 5 = 2^2 + 1^4
3 1 17 = 1^2 + 2^4
4 6 37 = 6^2 + 1^4
5 5 41 = 5^2 + 2^4
6 4 97 = 4^2 + 3^4
7 10 101 = 10^2 + 1^4
8 11 137 = 11^2 + 2^4
9 10 181 = 10^2 + 3^4
10 14 197 = 14^2 + 1^4
PROG
(PARI) See Links section.
CROSSREFS
See A002331, A331521, A331522, A331523, A331524, A331525, A331526 and A331527 for similar sequences.
Sequence in context: A359806 A346306 A021826 * A159927 A176443 A105225
KEYWORD
nonn
AUTHOR
Rémy Sigrist, Jan 18 2020
STATUS
approved