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A321351
a(n) is the index of the row of A321350 in which n first appears, or zero if n does not appear.
2
0, 1, 0, 26, 3, 0, 19, 5, 0, 21, 7, 0, 23, 9, 0, 25, 11, 0, 27, 13, 0, 29, 15, 0, 2, 17, 0, 4, 19, 0, 6, 21, 0, 8, 23, 0, 10, 25, 0, 12, 27, 0, 14, 29, 0, 16, 31, 0, 18, 33, 0, 20, 35, 0, 22
OFFSET
1,4
COMMENTS
No multiple of 3 appears, so a(3n) = 0 for all n.
FORMULA
a(n) <= (2/3)*n + 15 for n > 6.
EXAMPLE
a(5) = 3, since in A321350, 2 --> (2+3)^2 --> 5, so 5 first appears in the third row.
CROSSREFS
Sequence in context: A037929 A036167 A040675 * A040663 A040664 A040665
KEYWORD
nonn,hard
AUTHOR
Jeremy F. Alm, Nov 06 2018
STATUS
approved