520695

Appears in sequences

• Start with Pascal's triangle; form a rhombus by sliding down n steps from top on both sides then sliding down inwards to complete the rhombus and then deleting the inner numbers; a(n) = sum of entries on perimeter of rhombus.at n=10A081495
• Numbers k such that both k and k+1 are bi-unitary abundant numbers.at n=25A318167
• Numbers k such that both k and k+1 are infinitary abundant numbers (A129656).at n=7A327635
• Starts of runs of 3 consecutive Niven numbers in base 3/2 (A342426).at n=15A342428