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A117799
Icosagonal numbers for which the sum of the digits is also an icosagonal number.
0
0, 1, 7337, 12692, 19505, 37505, 61337, 75440, 146432, 240752, 326801, 358400, 620417, 708401, 802217, 851312, 1007345, 1062272, 1176500, 1235801, 1422452, 1622225, 1835120, 1909001, 2061137, 2219105, 2300276, 2728001, 4010672, 4803401, 5043017, 5165012, 7026032, 7315220, 7462001
OFFSET
1,3
EXAMPLE
7337 is in the sequence because (1) it is an icosagonal number and (2) the sum of the digits 7+3+3+7=20 is also an icosagonal number.
PROG
(PARI) isok(n) = ispolygonal(n, 20) && ispolygonal(sumdigits(n), 20); \\ Michel Marcus, Feb 27 2014
CROSSREFS
Sequence in context: A295004 A202167 A235883 * A295003 A097696 A202574
KEYWORD
nonn,base
AUTHOR
Luc Stevens (lms022(AT)yahoo.com), Apr 29 2006
EXTENSIONS
a(11) corrected by Georg Fischer, Mar 27 2024
STATUS
approved