Journal of Integer Sequences, Vol. 29 (2026), Article 26.5.7

Integer Sequences from Card-Dealing Patterns


Eric Huang1, Tanya Khovanova2, Timur Kilybayev1, Ryan Li1, Brandon Ni1, Leone Seidel1, Samarth Sharma1, Nathan Sheffield3, Vivek Varanasi1, Alice Yin1, Boya Yun1, and William Zelevinsky1

1PRIMES STEP
Department of Mathematics
Massachusetts Institute of Technology
Room 2-231c
77 Massachusetts Avenue
Cambridge, MA 02139
USA

2Department of Mathematics
Massachusetts Institute of Technology
Room 2-231c
77 Massachusetts Avenue
Cambridge, MA 02139-4307
USA

3Computer Science and Artificial Intelligence Laboratory
Massachusetts Institute of Technology
32 Vassar Street
Cambridge, MA 02139
USA

Abstract:

We define a card-dealing procedure by an infinite word with the letters U and D: a U-move sends the top card to the bottom of the deck, while a D-move removes the top card. For each pattern, we study five associated objects: the move-count sequence; the dealing triangle, whose entries give the removal rank of each initial position; its inverse, the Josephus triangle; the initial position of the last card removed; and the removal rank of the initial top card. A single round of the procedure gives simultaneous recursions for all five objects. For periodic patterns, we obtain additional row recurrences, and for the under-down shuffle, we express the dealing triangle explicitly in terms of the 2-adic valuation. We collect the resulting OEIS entries, including the 44 sequences introduced in the course of this project.


Full version:  pdf,    dvi,    ps,    latex    


(Concerned with sequences A000012 A000079 A000096 A000225 A001651 A005408 A005843 A006257 A007494 A008585 A008586 A016777 A016789 A032766 A038754 A054995 A062318 A081614 A081615 A088333 A152423 A164123 A181281 A182459 A225381 A291317 A321298 A337191 A360268 A378635 A378674 A378682 A380195 A380201 A380202 A380204 A380246 A380247 A380248 A381048 A381049 A381050 A381051 A381114 A381127 A381128 A381129 A381151 A381591 A381622 A381623 A381667 A382354 A382355 A382356 A382358 A382528 A383076 A383845 A383846 A383847 A384770 A384772 A384774 A385327 A385328 A385333 A385513 A386305 A386312 A386639 A386641 A386643.)


Received November 11 2025; revised versions received September 14 2026; October 11 2026; October 15 2026. Published in Journal of Integer Sequences, October 15 2026.


Return to Journal of Integer Sequences home page