A350766 Reversed sum of the two previous terms, with a(1) = 1 and a(2) = 11.

1, 11, 21, 23, 44, 76, 21, 79, 1, 8, 9, 71, 8, 97, 501, 895, 6931, 6287, 81231, 81578, 908261, 938989, 527481, 746641, 2214721, 2631692, 3146484, 6718775, 9525689, 46444261, 5996955, 61214425, 8311276, 10752596, 27836091, 78688583

Offset

1,2

Comments

Given two initial terms, sum the terms and reverse the digits of the sum. Then repeat.

Related to A014258, the Iccanobif numbers, but with initial terms 1 and 11 rather than 0 and 1.

Links

Table of n, a(n) for n=1..36.

Mathematica

Clear[ BiF ]; BiF[ 0 ]=1; BiF[ 1 ]=11; BiF[ n_Integer ] := BiF[ n ]=Plus@@(IntegerDigits[ BiF[ n-2 ]+BiF[ n-1 ], 10 ]//(#*Array[ 10^#&, Length[ # ], 0 ])&); Array[ BiF, 40, 0 ]
nxt[{a_, b_}]:={b, FromDigits[Reverse[IntegerDigits[a+b]]]}; Transpose[ NestList[ nxt, {0, 1}, 40]][[1]]

Prog

(Python)
terms = [1, 11]
for i in range(100):
    terms.append(int(str(terms[-1]+terms[-2])[::-1]))
print(terms) # Gleb Ivanov, Jan 14 2022

Crossrefs

Cf. A014258 but with initial terms 1 and 11 rather than 0 and 1.

Sequence in context: A178413 A050718 A360372 * A189226 A261409 A195100

Adjacent sequences: A350763 A350764 A350765 * A350767 A350768 A350769

Keyword

nonn,base,easy

Author

Tim Ricchuiti, Jan 14 2022

Status

approved