OFFSET
3,1
LINKS
Lucas A. Brown, Python program.
Eric Weisstein's World of Mathematics, Polygonal Number
EXAMPLE
a(5) = 210 because 210 has 5 pentagonal divisors {1, 5, 35, 70, 210} and this is the smallest such number.
PROG
(PARI) a(n) = my(k=1); while (sumdiv(k, d, ispolygonal(d, n)) != n, k++); k; \\ Michel Marcus, Nov 21 2022
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Nov 21 2022
EXTENSIONS
a(12)-a(13) from Michel Marcus, Nov 21 2022
a(14)-a(16) from Daniel Suteu, Dec 04 2022
a(17)-a(28) from Martin Ehrenstein, Dec 05 2022
STATUS
approved