This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A347114 #14 Mar 26 2022 19:12:57 %S A347114 1386470925,1423809765,1463095872,1536942870,1560837942,1583406972, %T A347114 1640538297,1738402695,1765403829,1795023846,1920538647,2056743198, %U A347114 2076149583,2089571436,2097384615,2301546897,2386051749,2453718609,2531869704,2587063149,2605431798 %N A347114 Heptagonal pandigitals. %C A347114 There are 53 pandigital heptagonal numbers with no repeated digits, i.e., 10-digit pandigital heptagonal numbers. - _Harvey P. Dale_, Mar 26 2022 %F A347114 Intersection of A000566 (heptagonal numbers) and A171102 (infinite pandigital numbers). %t A347114 h[n_] := n*(5*n - 3)/2; Select[h /@ Range[33000], Length @ DeleteDuplicates @ IntegerDigits[#] == 10 &] (* _Amiram Eldar_, Aug 19 2021 *) %t A347114 Select[PolygonalNumber[7,Range[20234,62854]],Sort[IntegerDigits[#]] == Range[ 0,9]&] (* _Harvey P. Dale_, Mar 26 2022 *) %o A347114 (Sage) %o A347114 A000566 = list(int(n*(5*n-3)/2) for n in range(0,1000000)) %o A347114 def haspan(s): return any(len(set(s[i:i+10]))==10 for i in range(len(s)-9)) %o A347114 A347114 = list(elem for elem in A000566 if haspan(str(elem))) %Y A347114 Cf. A000566, A171102. %K A347114 nonn,base,less %O A347114 1,1 %A A347114 _Dumitru Damian_, Aug 19 2021