cp's OEIS Frontend

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.

A347114 Heptagonal pandigitals.

Original entry on oeis.org

1386470925, 1423809765, 1463095872, 1536942870, 1560837942, 1583406972, 1640538297, 1738402695, 1765403829, 1795023846, 1920538647, 2056743198, 2076149583, 2089571436, 2097384615, 2301546897, 2386051749, 2453718609, 2531869704, 2587063149, 2605431798
Offset: 1

Views

Author

Dumitru Damian, Aug 19 2021

Keywords

Comments

There are 53 pandigital heptagonal numbers with no repeated digits, i.e., 10-digit pandigital heptagonal numbers. - Harvey P. Dale, Mar 26 2022

Crossrefs

Programs

  • Mathematica
    h[n_] := n*(5*n - 3)/2; Select[h /@ Range[33000], Length @ DeleteDuplicates @ IntegerDigits[#] == 10 &] (* Amiram Eldar, Aug 19 2021 *)
    Select[PolygonalNumber[7,Range[20234,62854]],Sort[IntegerDigits[#]] == Range[ 0,9]&] (* Harvey P. Dale, Mar 26 2022 *)
  • Sage
    A000566 = list(int(n*(5*n-3)/2) for n in range(0,1000000))
    def haspan(s): return any(len(set(s[i:i+10]))==10 for i in range(len(s)-9))
    A347114 = list(elem for elem in A000566 if haspan(str(elem)))

Formula

Intersection of A000566 (heptagonal numbers) and A171102 (infinite pandigital numbers).