Palindromic Triangular Numbers with Palindromic Index/Historical Note

Historical Note on Palindromic Triangular Numbers with Palindromic Index

David Wells reports in Curious and Interesting Numbers, 2nd ed. that Charles Ashbacher reports on this sequence (in particular $363 \, 474 \, 363$) in Journal of Recreational Mathematics, Volume $24$, page $184$, but this has not been corroborated.

Sources

• 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $363,474,363$