I was looking at the 1976 DETECTIVE COMICS issues with the Calculator, in backups in DETECTIVE 463-467, and concluded in a full length story in 468 (Rogers' first lead Batman story).

The first two Calculator backup stories are Mike Grell/Terry Austin art, 6 pages each.
DETECIVE 463 https://comiconlinefree.com/detective-comics-1937/issue-463/25
DETECTIVE 464 https://comiconlinefree.com/detective-comics-1937/issue-464/25

One issue with Ernie Chan (as Chua)/Austin art (6 pages):
DETECTIVE 465 https://comiconlinefree.com/detective-comics-1937/issue-465/24

Then a huge step up with two Marshall Rogers/Austin 6-page backups:
DETECTIVE 466 (6 pages) https://comiconlinefree.com/detective-comics-1937/issue-466/25
DETECTIVE 467 (6 pages) https://comiconlinefree.com/detective-comics-1937/issue-467/26

And then a full-length conclusion to the Calculator storyline by Rogers/Austin (17 pages) :
DETECTIVE 468 https://comiconlinefree.com/detective-comics-1937/issue-467/1

Then what I think was a lost opportunity in issues 469 and 470, that had a disastrous penciller/inker combination of Simonson/Milgrom art:
https://comiconlinefree.com/detective-comics-1937/issue-469/1
https://comiconlinefree.com/detective-comics-1937/issue-470/1

And then the series went into the classic Englehart/Rogers/Austin run.

But WHAT IF... issues 469 and 470 had been Simonson pencils with Marshall Rogers inks? That would have perfectly bridged the Calculator and Englehart runs, and potentially done so with a really interesting artist collaboration. Alas, a missed opportunity.

I think people remember the famous Englehart/Rogers run, but despite that the Calculator issues were just a few issues before it, that run is largely forgotten.

And likewise, the O'Neil/Rogers story in DETECTIVE 481 is also largely forgotten.
https://comiconlinefree.com/detective-comics-1937/issue-481/1
Often when the other Englehart/Rogers issues have been reprinted (in the 1986 reprint series SHADOW OF THE BATMAN 1-5, and in the BATMAN: STRANGE APPARITIONS trade) only 469-479 are reprinted, and the others not included. That's why I think the others are forgotten, they are treated as less valuable and less important. And not reprinted, they are mostly forgotten despite being nice work.