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A377094
Inverse permutation to A377093.
2
1, 2, 4, 3, 7, 5, 12, 19, 6, 8, 27, 38, 50, 13, 9, 20, 63, 80, 98, 10, 14, 28, 117, 21, 11, 51, 140, 15, 167, 196, 226, 22, 29, 64, 16, 39, 257, 99, 52, 23, 294, 17, 335, 30, 378, 118, 423, 24, 18, 470, 65, 53, 520, 81, 31, 25, 100, 168, 573, 40, 632, 227, 693
OFFSET
1,2
FORMULA
a(n) <= (n-1)*n/2 + 1. - Michael S. Branicky, Oct 16 2024
EXAMPLE
A377093(42) = 84, so a(84) = 42.
PROG
(C++) // See Links section.
(Python)
from itertools import count, islice
def agen(): # generator of terms; uses A377093gen() in A377093
adict, n = dict(), 1
for k, v in enumerate(A377093gen(), 1):
if v not in adict:
adict[v] = k
while n in adict: yield adict[n]; n += 1
print(list(islice(agen(), 63))) # Michael S. Branicky, Oct 16 2024
CROSSREFS
Cf. A377093.
Sequence in context: A258237 A361939 A371237 * A108228 A127008 A199535
KEYWORD
nonn
AUTHOR
Rémy Sigrist, Oct 16 2024
STATUS
approved