## Taxi! by Ilver

### Puzzle explanation

Extra letters in wordplay gave “a very interesting number”, the Indian mathematician Srinivasa Ramanujan’s description of 1729 (now known as the Hardy-Ramanujan number). Fellow mathematician G. H. Hardy, having travelled to visit Ramanujan in a taxi numbered 1729, remarked that it seemed a rather dull number, but Ramanujan pointed out that it was the smallest integer that is the sum of two (positive) cubes in two different ways, 1729 = 1³ + 12³ and 1729 = 9³ + 10³.

Taking letters in positions 1, 7, 2, 9, 1, 7, 2, 9, ... of successive across clues spelt out the start of Hardy’s statement “Beauty is the first test: there is no permanent place in the world for ugly mathematics”. Letters in columns 1/7 and 2/9 of alternate rows in the grid were THE WOR(AHSTTMMAEIC)LD, HARDY. Unscrambling MATHEMATICS completed a representation of Euler’s identity, e + 1 = 0, considered an example of mathematical beauty.

### Clue explanations

Conventions: * = anagram, < = reversal

Across
1 TRACKS T + RACKS
5 HOMAGE MAG in HOE
9 SEPHEN S(t)EPHEN
11 EH WHOW (n)E(p)H(e)W(’s) + HOW
13 EAT CROW TEA * + C + ROW
14 TARMAC (T CAR) * around MA
15 THARS T + HARS(h)
18 TAIPAN PIÑATA *
21 ENMESH MEN * + HE’S *
22 MYOSIN M + SOY < + IN
27 LETS GO LEGO around T(omb)S
29 SHINER (backwa)SH I NER(vously)
30 CARON CAR + ON
31 LYSINE IS < in LYNE
33 WHYDAHS WHY + D + HAS *
35 ASTRUT TR(ee) in (AS + UT)
36 RULE OK ULE in ROK
37 IDEATE IDE + AT + E
38 IDYLLS SILLY * around D
Down
1 TSOTSI T(u)S(k) O(n) T(h)[A](i) S(h)I(p)
2 RED ANT RANT around [V]ED
3 CHAMPIONESS CONES around (HAM + PI[E]) + S
4 KETA T[R] in KEA
5 HERB TEAS (B + STA[Y] HERE) *
6 OHO OH[I]O
7 AHEAP A + H + PA[N]E <
8 EWES E + WES[T]
10 PERIPLUS PULPITE[E]RS * − T
12 OKRAS RAS after [R]OK
15 TANE T[E]A + ’N’ + E
17 GONOCYTE GONE around (O + CY[S]T)
19 IMPISHLY IMPLY around [T]HIS *
20 EQUAL SIGN E + QUA[I]LS + IG + N