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A359093
a(n) is the index of the smallest n-gonal number whose sum of digits is n.
0
2, 2, 2, 2, 2, 2, 2, 10, 11, 6, 7, 11, 11, 4, 11, 9, 10, 29, 24, 29, 29, 29, 29, 29, 36, 28, 83, 69, 79, 110, 56, 83, 110, 72, 164, 236, 119, 178, 299, 209, 218, 308, 216, 416, 596, 506, 277, 443, 579, 589, 1172, 1217, 991, 1676, 1779, 2315, 1325, 1659, 3125, 2576
OFFSET
3,1
LINKS
Eric Weisstein's World of Mathematics, Polygonal Number
MATHEMATICA
p[n_, k_] := (n - 2)*k*(k - 1)/2 + k; a[n_] := Module[{k = 1}, While[Plus @@ IntegerDigits[p[n, k]] != n, k++]; k]; Array[a, 60, 3] (* Amiram Eldar, Dec 16 2022 *)
CROSSREFS
Sequence in context: A248771 A339446 A339166 * A291721 A109913 A197169
KEYWORD
nonn,base
AUTHOR
Ilya Gutkovskiy, Dec 16 2022
STATUS
approved