A155894 -id:A155894 - cp's OEIS frontend

A155895 Least positive integer such that a(n)! starts with n, both written in base 5.

1, 2, 17, 4, 6, 3, 29, 7, 10, 19, 31, 8, 18, 14, 37, 61, 81, 17, 33, 11, 63, 94, 9, 4, 13, 24, 16, 6, 27, 22, 52, 152, 28, 21, 143, 45, 35, 29, 67, 7, 62, 15, 247, 181, 193, 10, 105, 48, 12, 97, 19, 167, 36, 72, 146, 75, 31, 391, 69, 40, 186, 486, 133, 8, 57, 46, 18, 103, 115

Offset: 1

M. F. Hasler, Feb 01 2009

			a(3) = 17 since 17! is the least factorial to start with digit "3" when written in base 5. a(5) = 6 since 5 = 10[5] (i.e. written in base 5) and 6! = 720 = 625 + 75 + 20 = 10340[5] is the smallest factorial to start with digits "10" when written in base 5.

Cf. A155891--A155894, A018799, A076219.

A155895(n)={ local( F=1,k=1 ); while( F\1!=n, F*=k++; while( F>=n+1, F/=5)); k}

A155896 Least positive integer such that a(n)! starts with n, both written in base 6.

Original entry on oeis.org

1, 2, 5, 4, 8, 3, 9, 26, 52, 18, 25, 10, 33, 53, 32, 15, 13, 20, 30, 5, 17, 42, 7, 4, 23, 43, 78, 50, 28, 113, 8, 44, 19, 334, 59, 100, 195, 27, 22, 14, 91, 172, 371, 16, 93, 9, 12, 102, 66, 26, 46, 95, 279, 303, 69, 331, 272, 52, 286, 79, 264, 298, 18, 21, 190, 104, 47, 138, 255

Offset: 1

M. F. Hasler, Feb 01 2009

			a(3) = 5 since 5!=120 is the least factorial to start with digit "3" when written in base 6. a(8) = 26 since 8 = 12[6] (i.e. written in base 6) and 26! is the smallest factorial to start with digits "12" when written in base 6.

Cf. A155891--A155894, A018799, A076219.

A155896(n)={ local( F=1,k=1 ); while( F\1!=n, F*=k++; while( F>=n+1, F/=6)); k}

cp's OEIS Frontend

A155895 Least positive integer such that a(n)! starts with n, both written in base 5.

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